[CI Skip] release/stable 6.12.1

skip-checks: true
6.12.1 (#4326 )
2021-12-13 08:29:38 +00:00 · 2021-12-13 10:20:32 +02:00 · 2021-12-13 06:21:35 +00:00 · 2021-12-13 08:13:54 +02:00 · 2021-12-12 09:51:00 +00:00 · 2021-12-12 11:44:20 +02:00
393 changed files with 38676 additions and 21400 deletions
@@ -39,3 +39,10 @@
 6.0.4
 6.0.5
 6.1.2
+
+6.4.2
+6.5.2
+6.7.2
+6.9.2
+6.10.2
+6.10.3
@@ -1,3 +1,17 @@
+checks:
+  argument-count:
+    config:
+      threshold: 5
+  method-complexity:
+    config:
+      threshold: 7
+  method-count:
+    config:
+      threshold: 25
+  method-lines:
+    config:
+      threshold: 30
+
 exclude_patterns:
 - "**/*.spec.js"
 - "**/*.spec.ts"
@@ -2,7 +2,7 @@ name: 'Lock Threads'

 on:
  schedule:
-    - cron: '30 1/2 * * *'
+    - cron: '10 1/3 * * *'

 jobs:
  lock:
@@ -1,7 +1,7 @@
 name: 'Close stale issues and PRs'
 on:
  schedule:
-    - cron: '30 2/2 * * *'
+    - cron: '55 1/3 * * *'

 jobs:
  stale:
@@ -21,6 +21,7 @@ tmp/
 cc-test-reporter
 lerna-debug.log*
 npm-debug.log*
+package-lock.json
+tsconfig.*buildinfo
 yarn-debug.log*
 yarn-error.log*
-package-lock.json
@@ -1,5 +1,197 @@
 # CHANGELOG

+## 6.12.1 Dec 13, 2021
+
+Upgrade priority: Low. Recommended for users of contracts on the current Substrate master version and TS users who generate metadata v14 interfaces.
+
+Changes:
+
+- Add support for contracts V2 ABI metadata
+- `CheckNonZeroSender` signed extension support
+- Remove old-style capabilities detection (unneeded with metadata v14+)
+- Generated TS Enum interfaces now expose the `type` (with allowed values)
+- Split local & package imports in generated TS interfaces
+- Add Kusama 9130 upgrade block
+- Internal maintainability cleanups
+
+
+## 6.11.1 Dec 5, 2021
+
+Upgrade priority: Low. Maintenance upgrade, tracking the latest `@polkadot` libraries.
+
+Changes:
+
+- Align `state_traceBlock` RPC with Substrate
+- Bump static metadata for latest Substrate, Polkadot & Kusama
+
+
+## 6.10.3 Nov 30, 2021
+
+Upgrade priority: Medium. Recommended for 6.10.x users
+
+Changes:
+
+- Fix ss58Prefix extraction
+
+
+## 6.10.2 Nov 30, 2021
+
+Upgrade priority: Low. Aligns TS augmentation and decoration with older behavior for ALL_CAPS identifiers.
+
+Changes:
+
+- Adjust augmentation interface consistency with top-level declarations
+- Update `@polkadot/util` to 8.0.4 with adjusted `stringCamelCase`
+
+
+## 6.10.1 Nov 29, 2021
+
+Upgrade priority: Low. Recommended for users of `HttpProvider` and for chains generating types using TS augmentation.
+
+Changes:
+
+- Fix for HttpProvider init (RPC sections with only subscriptions)
+- Re-order imports in lookup type augmentation interfaces
+- Bump static metadata for latest Substrate, Polkadot & Kusama
+
+
+## 6.9.2 Nov 22, 2021
+
+Upgrade priority: Medium. Pulls in `@polkadot/util-crypto` fix for TS projects.
+
+Changes:
+
+- Update `@polkadot/util-crypto` with TS compilation work-around
+
+
+## 6.9.1 Nov 21, 2021
+
+Upgrade priority: Medium. Recommended for metadata v14 parachains. For TS users, the package now support TypeScript 4.5.2 and allows extraction of user types from metadata v14.
+
+Contributed:
+
+- Lookup TS generation for all metadata v14 chains (Thanks to https://github.com/savudani8)
+- Update `BeefySignedCommitment` type (Thanks to https://github.com/czl1378)
+
+Changes:
+
+- Adjust runtime `*::{Call, Event}` matching for metadata v14
+- Adjust derive decoration with (optional) known methods
+- Expose `*{Call, Event, Error}` TS types for metadata v14
+- Align Option `.toJSON` output with Substrate input
+- Optimize Enum, Struct, Option & Number decoding paths
+- Ajust PascalCase conversions with function from util
+- Prepare pre-v13 types for optional injection
+- Adjustments for TS 4.5.2 support (flatten type infers)
+
+
+## 6.8.1 Nov 11, 2021
+
+Upgrade priority: Low. Recommended for chains with non-MultiSignature variants where `paymentInfo` is required.
+
+Changes:
+
+- Adjust `paymentInfo` signatures to cater for non-MultiSignature variants
+- Remove `::generic::` from names & namespaces under metadata v14
+- Add Polkadot 9122 upgrade block
+- Cleanup Polkadot/Kusama/Westend/Rococo known types (>= v14 metadata)
+- Internal `decorateMethod{Promise, Rx}` renamed to `to{Promise, Rx}Method`
+- Add RPC provider-level LRU for historic requests
+- Add optional known runtime version param to internal `rx.queryAt`
+
+
+## 6.7.2 Nov 9, 2021
+
+Upgrade priority: Low. Recommended for chains on metadata v14 with non-default `Address` implementations.
+
+Changes:
+
+- Detect `AccountId` & `Address` types via `SpRuntime*` definitions
+- Adjust api-derive call ordering when using `.queryAt`
+
+
+## 6.7.1 Nov 7, 2021
+
+Upgrade priority: Low. Internal maintenance updates, focussed on internal optimizations.
+
+Changelog:
+
+- Optimize Extrinsic & block handling (Thanks to https://github.com/nazar-pc)
+- Add `account::AccountId20` mapping (Thanks to https://github.com/joelamouche)
+
+Changes:
+
+- Use new-gen `voteLockingPeriod` in democracy derives (as available)
+- Dynamically inject getters for `Extrinsic` payloads
+- Optimize caching for complex constructed type classes per registry
+- Convert metadata, rpc and api to use lazy decoration
+- Split u8a decoding paths for `Vec` (different from general path)
+- Keep track of initial u8a decoded length inside base Codecs
+- Extract multi property assignments for `Struct`, `Set`, `Json` & `Enum`
+- Move `PortableRegistry` location inside `@polkadot/types/metadata`
+- Bump static metadata for latest Substrate, Polkadot & Kusama
+
+
+## 6.6.1 Nov 1, 2021
+
+Upgrade priority: Low. Internal maintenance updates.
+
+Changes:
+
+- Fix construction for `palletVersion` keys with correct prefix
+- Add Polkadot `EthereumAddress` as a known `PortableRegistry` override
+- De-dupe `PortableRegistry` namespace splitting operations
+- Optimize internal `AbstractArray` & `Struct` u8a decoding
+- Shortcut `Struct` construction from `Struct` instance
+- Use internal `lookupName` in `createClass` (allows deeply recursive lookups)
+- Codec `toHex()` will now correctly return the TS `HexString` type
+- Update known upgrade blocks for Westend & Kusama
+- Bump static metadata for latest Substrate, Polkadot & Kusama
+
+
+## 6.5.2 Oct 26, 2021
+
+Upgrade priority: Low. Recommended for users with `.at` queries on unknown blocks.
+
+Changes:
+
+- Adjust `toHuman` on `Call` to return names & (not only) values
+- Allow for optional known `RuntimeVersion` to short-circuit `api.at`
+- Ensure `Struct` decodes fully on `null` input (equivalent to `undefined` & `{}`)
+
+
+## 6.5.1 Oct 24, 2021
+
+Upgrade priority: Low. Internal maintenance upgrades.
+
+Contributed:
+
+- Add `Auction` to Polkadot pre-0.9.11 `ProxyType` (Thanks to https://github.com/wirednkod)
+
+Changes:
+
+- Ecah module now exposes the Substrate-added `palletVersion` storage item
+- Adjust Websocket `maxReceivedFrameSize` under Node
+- `TypeDef` structures now contain the `typeName` from metadata v14 on fields
+- Fix browser bundle imports for xcm-mapping (move to `types-known`)
+- Expose all extracted type names in `PortableRegistry`
+- Adjust `toJSON` (Ascii) output detection on `Raw`
+- Adjust `api.rpc.*.*.raw(..args)` return to the actual over-the-wire JSON result
+- Remove `api.rpc.*.*.json(..args)` since it now overlaps with new `.raw`
+- Bump static metadata for latest Substrate, Polkadot & Kusama
+
+
+## 6.4.2 Oct 18, 2021
+
+Upgrade priority: Low. Recommended for Westmint runtime 500+
+
+Changes:
+
+- Ensure `SignerPayload` correctly serializes `Option` with `None`
+- Add Ethereum `BlockV{0, 1, 2}` types, aligning with latest Frontier
+- Additional tests for metadata serialization/de-serialization
+
+
 ## 6.4.1 Oct 17, 2021

 Upgrade priority: Low. Recommended for Kusama & Polkadot runtime 9110+
@@ -1,40 +1,46 @@
 {
-  "repository": "https://github.com/polkadot-js/api",
  "author": "Jaco Greeff <jacogr@gmail.com>",
+  "bugs": "https://github.com/polkadot-js/api/issues",
+  "homepage": "https://github.com/polkadot-js/api#readme",
  "license": "Apache-2",
+  "packageManager": "yarn@3.0.1",
  "private": true,
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/polkadot-js/api.git"
+  },
+  "sideEffects": false,
  "type": "commonjs",
+  "version": "6.12.1",
  "workspaces": [
    "packages/*"
  ],
-  "resolutions": {
-    "typescript": "^4.4.4"
-  },
  "scripts": {
    "build": "yarn build:interfaces && polkadot-dev-build-ts",
    "build:extra": "(cd packages/typegen && copyfiles scripts/* build)",
    "build:interfaces": "polkadot-types-internal-interfaces",
    "build:release": "polkadot-ci-ghact-build",
    "build:rollup": "polkadot-exec-rollup --config",
-    "docs:metadata": "polkadot-types-internal-metadata",
    "chain:info": "polkadot-types-chain-info",
-    "lint": "polkadot-dev-run-lint",
    "clean": "polkadot-dev-clean-build",
+    "docs:metadata": "polkadot-types-internal-metadata",
+    "lint": "polkadot-dev-run-lint",
    "postinstall": "polkadot-dev-yarn-only",
    "test": "polkadot-dev-run-test --coverage --forceExit --runInBand --testPathIgnorePatterns e2e",
    "test:one": "polkadot-dev-run-test --detectOpenHandles --forceExit",
    "test:watch": "polkadot-dev-run-test --watch"
  },
  "devDependencies": {
-    "@babel/core": "^7.15.8",
-    "@babel/register": "^7.15.3",
-    "@babel/runtime": "^7.15.4",
-    "@polkadot/dev": "^0.63.3",
-    "@polkadot/ts": "^0.4.9",
+    "@babel/core": "^7.16.0",
+    "@babel/register": "^7.16.0",
+    "@babel/runtime": "^7.16.3",
+    "@polkadot/dev": "^0.63.39",
+    "@polkadot/ts": "^0.4.18",
    "@polkadot/typegen": "workspace:packages/typegen",
-    "@types/jest": "^27.0.2",
+    "@types/jest": "^27.0.3",
    "copyfiles": "^2.4.1"
  },
-  "version": "6.4.1",
-  "packageManager": "yarn@3.0.1"
+  "resolutions": {
+    "typescript": "^4.5.3"
+  }
 }
@@ -1,28 +1,32 @@
 {
-  "name": "@polkadot/api-contract",
-  "version": "6.4.1",
-  "type": "module",
+  "author": "Jaco Greeff <jacogr@gmail.com>",
+  "bugs": "https://github.com/polkadot-js/api/issues",
+  "contributors": [],
  "description": "Interfaces for interacting with contracts and contract ABIs",
-  "main": "index.js",
+  "engines": {
+    "node": ">=14.0.0"
+  },
+  "homepage": "https://github.com/polkadot-js/api/tree/master/packages/api-contract#readme",
+  "license": "Apache-2.0",
+  "maintainers": [],
+  "name": "@polkadot/api-contract",
+  "repository": {
+    "directory": "packages/api-contract",
+    "type": "git",
+    "url": "https://github.com/polkadot-js/api.git"
+  },
  "sideEffects": [
    "./detectPackage.js",
    "./detectPackage.cjs"
  ],
-  "engines": {
-    "node": ">=14.0.0"
-  },
-  "author": "Jaco Greeff <jacogr@gmail.com>",
-  "maintainers": [],
-  "contributors": [],
-  "license": "Apache-2.0",
-  "repository": "github:polkadot-js/api",
-  "bugs": "https://github.com/polkadot-js/api/issues",
-  "homepage": "https://github.com/polkadot-js/api/tree/master/packages/api-contract#readme",
+  "type": "module",
+  "version": "6.12.1",
+  "main": "index.js",
  "dependencies": {
-    "@babel/runtime": "^7.15.4",
-    "@polkadot/api": "6.4.1",
-    "@polkadot/types": "6.4.1",
-    "@polkadot/util": "^7.5.1",
+    "@babel/runtime": "^7.16.3",
+    "@polkadot/api": "6.12.1",
+    "@polkadot/types": "6.12.1",
+    "@polkadot/util": "^8.1.2",
    "rxjs": "^7.4.0"
  }
 }
@@ -1,7 +1,7 @@
 // Copyright 2017-2021 @polkadot/api-contract authors & contributors
 // SPDX-License-Identifier: Apache-2.0

-import type { AnyJson, Registry } from '@polkadot/types/types';
+import type { Registry } from '@polkadot/types/types';

 import fs from 'fs';
 import path from 'path';
@@ -14,6 +14,7 @@ import { Abi } from '.';

 interface SpecDef {
  messages: {
+    label: string;
    name: string[] | string
  }[]
 }
@@ -28,6 +29,9 @@ interface JSONAbi {
  spec: SpecDef;
  V1: {
    spec: SpecDef;
+  },
+  V2: {
+    spec: SpecDef;
  }
 }

@@ -47,11 +51,19 @@ function stringifyJson (registry: Registry): string {

 describe('Abi', (): void => {
  describe('ABI', (): void => {
-    Object.entries(abis).forEach(([abiName, abi]: [string, JSONAbi]) => {
+    Object.entries(abis).forEach(([abiName, _abi]) => {
+      const abi = _abi as unknown as JSONAbi;
+
      it(`initializes from a contract ABI (${abiName})`, (): void => {
        try {
-          const messageIds = (abi.V1 ? abi.V1 : abi).spec.messages.map(({ name }) => Array.isArray(name) ? name[0] : name);
-          const inkAbi = new Abi(abis[abiName] as AnyJson);
+          const messageIds = (abi.V2 || abi.V1 || abi).spec.messages.map(({ label, name }) =>
+            label || (
+              Array.isArray(name)
+                ? name[0]
+                : name
+            )
+          );
+          const inkAbi = new Abi(abis[abiName]);

          expect(inkAbi.messages.map(({ identifier }) => identifier)).toEqual(messageIds);
        } catch (error) {
@@ -66,7 +78,7 @@ describe('Abi', (): void => {
  describe('TypeDef', (): void => {
    Object.keys(abis).forEach((abiName) => {
      it(`initializes from a contract ABI (${abiName})`, (): void => {
-        const abi = new Abi(abis[abiName] as AnyJson);
+        const abi = new Abi(abis[abiName]);
        const json = stringifyJson(abi.registry);
        const cmpPath = path.join(__dirname, `../../test/compare/${abiName}.test.json`);

@@ -87,8 +99,8 @@ describe('Abi', (): void => {
  });

  it('has the correct hash for the source', (): void => {
-    const bundle = abis.ink_v0_flipperBundle as JSONAbi;
-    const abi = new Abi(bundle as unknown as AnyJson);
+    const abi = new Abi(abis.ink_v0_flipperBundle);
+    const bundle = abis.ink_v0_flipperBundle as unknown as JSONAbi;

    // manual
    expect(bundle.source.hash).toEqual(blake2AsHex(bundle.source.wasm));
@@ -1,25 +1,15 @@
 // Copyright 2017-2021 @polkadot/api-contract authors & contributors
 // SPDX-License-Identifier: Apache-2.0

-import type { Bytes } from '@polkadot/types';
-import type { ChainProperties, ContractConstructorSpec, ContractEventSpec, ContractMessageParamSpec, ContractMessageSpec, ContractMetadataLatest, ContractProjectInfo } from '@polkadot/types/interfaces';
-import type { AnyJson, Codec, Registry } from '@polkadot/types/types';
+import type { Bytes, PortableRegistry } from '@polkadot/types';
+import type { ChainProperties, ContractConstructorSpecLatest, ContractEventSpecLatest, ContractMessageParamSpecLatest, ContractMessageSpecLatest, ContractMetadataLatest, ContractProjectInfo } from '@polkadot/types/interfaces';
+import type { Codec, Registry } from '@polkadot/types/types';
 import type { AbiConstructor, AbiEvent, AbiMessage, AbiParam, DecodedEvent, DecodedMessage } from '../types';

 import { TypeDefInfo, TypeRegistry } from '@polkadot/types';
 import { assert, assertReturn, compactAddLength, compactStripLength, isNumber, isObject, isString, logger, stringCamelCase, stringify, u8aConcat, u8aToHex } from '@polkadot/util';

-import { toLatest } from './toLatest';
-
-interface V0AbiJson {
-  metadataVersion: string;
-  spec: {
-    constructors: unknown[];
-    events: unknown[];
-    messages: unknown[];
-  };
-  types: unknown[];
-}
+import { v0ToLatest, v1ToLatest } from './toLatest';

 const l = logger('Abi');

@@ -35,17 +25,30 @@ function findMessage <T extends AbiMessage> (list: T[], messageOrId: T | string
  return assertReturn(message, () => `Attempted to call an invalid contract interface, ${stringify(messageOrId)}`);
 }

-function parseJson (json: AnyJson, chainProperties?: ChainProperties): [AnyJson, Registry, ContractMetadataLatest, ContractProjectInfo] {
+// FIXME: This is still workable with V0, V1 & V2, but certainly is not a scalable
+// approach (right at this point don't quite have better ideas that is not as complex
+// as the conversion tactics in the runtime Metadata)
+function getLatestMeta (registry: Registry, json: Record<string, unknown>): ContractMetadataLatest {
+  const metadata = registry.createType('ContractMetadata',
+    isObject(json.V2)
+      ? { V2: json.V2 }
+      : isObject(json.V1)
+        ? { V1: json.V1 }
+        : { V0: json }
+  );
+
+  return metadata.isV2
+    ? metadata.asV2
+    : metadata.isV1
+      ? v1ToLatest(registry, metadata.asV1)
+      : v0ToLatest(registry, metadata.asV0);
+}
+
+function parseJson (json: Record<string, unknown>, chainProperties?: ChainProperties): [Record<string, unknown>, Registry, ContractMetadataLatest, ContractProjectInfo] {
  const registry = new TypeRegistry();
  const info = registry.createType('ContractProjectInfo', json);
-  const metadata = registry.createType('ContractMetadata', isString((json as unknown as V0AbiJson).metadataVersion)
-    ? { V0: json }
-    : { V1: (json as Record<string, AnyJson>).V1 }
-  );
-  const latest = metadata.isV0
-    ? toLatest(registry, metadata.asV0)
-    : metadata.asV1;
-  const lookup = registry.createType('PortableRegistry', { types: latest.types });
+  const latest = getLatestMeta(registry, json);
+  const lookup = registry.createType<PortableRegistry>('PortableRegistry', { types: latest.types });

  // attach the lookup to the registry - now the types are known
  registry.setLookup(lookup);
@@ -69,7 +72,7 @@ export class Abi {

  public readonly info: ContractProjectInfo;

-  public readonly json: AnyJson;
+  public readonly json: Record<string, unknown>;

  public readonly messages: AbiMessage[];

@@ -77,22 +80,22 @@ export class Abi {

  public readonly registry: Registry;

-  constructor (abiJson: AnyJson, chainProperties?: ChainProperties) {
+  constructor (abiJson: Record<string, unknown> | string, chainProperties?: ChainProperties) {
    [this.json, this.registry, this.metadata, this.info] = parseJson(
      isString(abiJson)
-        ? JSON.parse(abiJson) as AnyJson
+        ? JSON.parse(abiJson) as Record<string, unknown>
        : abiJson,
      chainProperties
    );
-    this.constructors = this.metadata.spec.constructors.map((spec: ContractConstructorSpec, index) =>
+    this.constructors = this.metadata.spec.constructors.map((spec: ContractConstructorSpecLatest, index) =>
      this.#createMessage(spec, index, {
        isConstructor: true
      })
    );
-    this.events = this.metadata.spec.events.map((spec: ContractEventSpec, index) =>
+    this.events = this.metadata.spec.events.map((spec: ContractEventSpecLatest, index) =>
      this.#createEvent(spec, index)
    );
-    this.messages = this.metadata.spec.messages.map((spec: ContractMessageSpec, index): AbiMessage => {
+    this.messages = this.metadata.spec.messages.map((spec: ContractMessageSpecLatest, index): AbiMessage => {
      const typeSpec = spec.returnType.unwrapOr(null);

      return this.#createMessage(spec, index, {
@@ -139,15 +142,15 @@ export class Abi {
    return findMessage(this.messages, messageOrId);
  }

-  #createArgs = (args: ContractMessageParamSpec[], spec: unknown): AbiParam[] => {
-    return args.map(({ name, type }, index): AbiParam => {
+  #createArgs = (args: ContractMessageParamSpecLatest[], spec: unknown): AbiParam[] => {
+    return args.map(({ label, type }, index): AbiParam => {
      try {
        assert(isObject(type), 'Invalid type definition found');

        const displayName = type.displayName.length
          ? type.displayName[type.displayName.length - 1].toString()
          : undefined;
-        const camelName = stringCamelCase(name);
+        const camelName = stringCamelCase(label);

        if (displayName && PRIMITIVE_ALWAYS.includes(displayName)) {
          return {
@@ -175,7 +178,7 @@ export class Abi {
    });
  };

-  #createEvent = (spec: ContractEventSpec, index: number): AbiEvent => {
+  #createEvent = (spec: ContractEventSpecLatest, index: number): AbiEvent => {
    const args = this.#createArgs(spec.args, spec);
    const event = {
      args,
@@ -184,16 +187,16 @@ export class Abi {
        args: this.#decodeArgs(args, data),
        event
      }),
-      identifier: spec.name.toString(),
+      identifier: spec.label.toString(),
      index
    };

    return event;
  };

-  #createMessage = (spec: ContractMessageSpec | ContractConstructorSpec, index: number, add: Partial<AbiMessage> = {}): AbiMessage => {
+  #createMessage = (spec: ContractMessageSpecLatest | ContractConstructorSpecLatest, index: number, add: Partial<AbiMessage> = {}): AbiMessage => {
    const args = this.#createArgs(spec.args, spec);
-    const identifier = spec.name.toString();
+    const identifier = spec.label.toString();
    const message = {
      ...add,
      args,
@@ -237,8 +240,8 @@ export class Abi {
    return message.fromU8a(trimmed.subarray(4));
  };

-  #encodeArgs = ({ name, selector }: ContractMessageSpec | ContractConstructorSpec, args: AbiParam[], data: unknown[]): Uint8Array => {
-    assert(data.length === args.length, () => `Expected ${args.length} arguments to contract message '${name.toString()}', found ${data.length}`);
+  #encodeArgs = ({ label, selector }: ContractMessageSpecLatest | ContractConstructorSpecLatest, args: AbiParam[], data: unknown[]): Uint8Array => {
+    assert(data.length === args.length, () => `Expected ${args.length} arguments to contract message '${label.toString()}', found ${data.length}`);

    return compactAddLength(
      u8aConcat(
@@ -0,0 +1,73 @@
+// Copyright 2017-2021 @polkadot/api-contract authors & contributors
+// SPDX-License-Identifier: Apache-2.0
+
+import { TypeRegistry } from '@polkadot/types';
+
+import abis from '../../test/contracts';
+import { v0ToLatest, v1ToLatest } from './toLatest';
+
+describe('v0ToLatest', (): void => {
+  const registry = new TypeRegistry();
+  const contract = registry.createType('ContractMetadata', { V0: abis.ink_v0_erc20 });
+  const latest = v0ToLatest(registry, contract.asV0);
+
+  it('has the correct constructors', (): void => {
+    expect(
+      latest.spec.constructors.map(({ label }) => label.toString())
+    ).toEqual(['new']);
+  });
+
+  it('has the correct messages', (): void => {
+    expect(
+      latest.spec.messages.map(({ label }) => label.toString())
+    ).toEqual(['total_supply', 'balance_of', 'allowance', 'transfer', 'approve', 'transfer_from']);
+  });
+
+  it('has the correct events', (): void => {
+    expect(
+      latest.spec.events.map(({ label }) => label.toString())
+    ).toEqual(['Transfer', 'Approval']);
+  });
+
+  it('has the correct constructor arguments', (): void => {
+    expect(
+      latest.spec.constructors[0].args.map(({ label }) => label.toString())
+    ).toEqual(['initial_supply']);
+  });
+
+  it('has the correct message arguments', (): void => {
+    expect(
+      latest.spec.messages[1].args.map(({ label }) => label.toString())
+    ).toEqual(['owner']);
+  });
+
+  it('has the correct event arguments', (): void => {
+    expect(
+      latest.spec.events[0].args.map(({ label }) => label.toString())
+    ).toEqual(['from', 'to', 'value']);
+  });
+});
+
+describe('v1ToLatest', (): void => {
+  const registry = new TypeRegistry();
+  const contract = registry.createType('ContractMetadata', { V1: abis.ink_v1_flipper.V1 });
+  const latest = v1ToLatest(registry, contract.asV1);
+
+  it('has the correct constructors', (): void => {
+    expect(
+      latest.spec.constructors.map(({ label }) => label.toString())
+    ).toEqual(['new', 'default']);
+  });
+
+  it('has the correct messages', (): void => {
+    expect(
+      latest.spec.messages.map(({ label }) => label.toString())
+    ).toEqual(['flip', 'get']);
+  });
+
+  it('has the correct constructor arguments', (): void => {
+    expect(
+      latest.spec.constructors[0].args.map(({ label }) => label.toString())
+    ).toEqual(['init_value']);
+  });
+});
@@ -1,14 +1,16 @@
 // Copyright 2017-2021 @polkadot/api-contract authors & contributors
 // SPDX-License-Identifier: Apache-2.0

-import type { ContractMetadataLatest, ContractMetadataV0 } from '@polkadot/types/interfaces';
+import type { ContractMetadataLatest, ContractMetadataV0, ContractMetadataV1 } from '@polkadot/types/interfaces';
 import type { Registry } from '@polkadot/types/types';

-import { convertSiV0toV1 } from '@polkadot/types/generic/PortableRegistry';
+import { v0ToV1 } from './toV1';
+import { v1ToV2 } from './toV2';

-export function toLatest (registry: Registry, v0: ContractMetadataV0): ContractMetadataLatest {
-  return registry.createType('ContractMetadataLatest', {
-    ...v0,
-    types: convertSiV0toV1(registry, v0.types)
-  });
+export function v1ToLatest (registry: Registry, v1: ContractMetadataV1): ContractMetadataLatest {
+  return v1ToV2(registry, v1);
+}
+
+export function v0ToLatest (registry: Registry, v0: ContractMetadataV0): ContractMetadataLatest {
+  return v1ToLatest(registry, v0ToV1(registry, v0));
 }
@@ -0,0 +1,14 @@
+// Copyright 2017-2021 @polkadot/api-contract authors & contributors
+// SPDX-License-Identifier: Apache-2.0
+
+import type { ContractMetadataV0, ContractMetadataV1 } from '@polkadot/types/interfaces';
+import type { Registry } from '@polkadot/types/types';
+
+import { convertSiV0toV1 } from '@polkadot/types';
+import { objectSpread } from '@polkadot/util';
+
+export function v0ToV1 (registry: Registry, v0: ContractMetadataV0): ContractMetadataV1 {
+  return registry.createType('ContractMetadataV1', objectSpread({}, v0, {
+    types: convertSiV0toV1(registry, v0.types)
+  }));
+}
@@ -0,0 +1,52 @@
+// Copyright 2017-2021 @polkadot/api-contract authors & contributors
+// SPDX-License-Identifier: Apache-2.0
+
+import type { Text } from '@polkadot/types';
+import type { ContractMetadataV1, ContractMetadataV2 } from '@polkadot/types/interfaces';
+import type { InterfaceTypes, Registry } from '@polkadot/types/types';
+
+import { objectSpread } from '@polkadot/util';
+
+type WithArgs = keyof typeof ARG_TYPES;
+
+interface NamedEntry {
+  name: Text | Text[];
+}
+
+interface ArgsEntry <T extends WithArgs> extends NamedEntry {
+  args: InterfaceTypes[`${T}V0`]['args'][0][];
+}
+
+const ARG_TYPES = {
+  ContractConstructorSpec: 'ContractMessageParamSpecV2',
+  ContractEventSpec: 'ContractEventParamSpecV2',
+  ContractMessageSpec: 'ContractMessageParamSpecV2'
+};
+
+function v1ToV2Label (entry: NamedEntry): { label: Text } {
+  return objectSpread({}, entry, {
+    label: Array.isArray(entry.name)
+      ? entry.name[0]
+      : entry.name
+  });
+}
+
+function v1ToV2Labels <T extends WithArgs> (registry: Registry, outType: T, all: ArgsEntry<T>[]): unknown[] {
+  return all.map((e) =>
+    registry.createType(`${outType}V2`, objectSpread(v1ToV2Label(e), {
+      args: e.args.map((a) =>
+        registry.createType(ARG_TYPES[outType], v1ToV2Label(a))
+      )
+    }))
+  );
+}
+
+export function v1ToV2 (registry: Registry, v1: ContractMetadataV1): ContractMetadataV2 {
+  return registry.createType('ContractMetadataV2', objectSpread({}, v1, {
+    spec: objectSpread({}, v1.spec, {
+      constructors: v1ToV2Labels(registry, 'ContractConstructorSpec', v1.spec.constructors),
+      events: v1ToV2Labels(registry, 'ContractEventSpec', v1.spec.events),
+      messages: v1ToV2Labels(registry, 'ContractMessageSpec', v1.spec.messages)
+    })
+  }));
+}
@@ -2,7 +2,7 @@
 // SPDX-License-Identifier: Apache-2.0

 import type { ApiTypes, DecorateMethod } from '@polkadot/api/types';
-import type { AnyJson, Registry } from '@polkadot/types/types';
+import type { Registry } from '@polkadot/types/types';

 import { ApiBase } from '@polkadot/api/base';
 import { assert, isFunction } from '@polkadot/util';
@@ -16,14 +16,15 @@ export abstract class Base<ApiType extends ApiTypes> {

  protected readonly _decorateMethod: DecorateMethod<ApiType>;

-  constructor (api: ApiBase<ApiType>, abi: AnyJson | Abi, decorateMethod: DecorateMethod<ApiType>) {
+  constructor (api: ApiBase<ApiType>, abi: string | Record<string, unknown> | Abi, decorateMethod: DecorateMethod<ApiType>) {
    this.abi = abi instanceof Abi
      ? abi
      : new Abi(abi, api.registry.getChainProperties());
    this.api = api;
    this._decorateMethod = decorateMethod;

-    assert(!!(api && api.isConnected && api.tx && api.tx.contracts && Object.keys(api.tx.contracts).length), 'Your API has not been initialized correctly and it not decorated with the runtime interfaces for contracts as retrieved from the on-chain runtime');
+    assert(!!(api && api.isConnected && api.tx), 'Your API has not been initialized correctly and is not connected to a chain');
+    assert(!!(api.tx.contracts && Object.keys(api.tx.contracts).length), 'You need to connect to a chain with a runtime that supports contracts');
    assert(isFunction(api.tx.contracts.instantiateWithCode), 'You need to connect to a chain with a runtime with a V3 contracts module. The runtime does not expose api.tx.contracts.instantiateWithCode');
  }

@@ -4,7 +4,7 @@
 import type { SubmittableExtrinsic } from '@polkadot/api/submittable/types';
 import type { ApiTypes, DecorateMethod } from '@polkadot/api/types';
 import type { AccountId, EventRecord, Hash } from '@polkadot/types/interfaces';
-import type { AnyJson, ISubmittableResult } from '@polkadot/types/types';
+import type { ISubmittableResult } from '@polkadot/types/types';
 import type { AbiConstructor, BlueprintOptions } from '../types';
 import type { MapConstructorExec } from './types';

@@ -18,6 +18,10 @@ import { Base } from './Base';
 import { Contract } from './Contract';
 import { createBluePrintTx, encodeSalt } from './util';

+export interface BlueprintConstructor<ApiType extends ApiTypes> {
+  new(api: ApiBase<ApiType>, abi: string | Record<string, unknown> | Abi, codeHash: string | Hash | Uint8Array): Blueprint<ApiType>;
+}
+
 export class BlueprintSubmittableResult<ApiType extends ApiTypes> extends SubmittableResult {
  public readonly contract?: Contract<ApiType>;

@@ -36,7 +40,7 @@ export class Blueprint<ApiType extends ApiTypes> extends Base<ApiType> {

  readonly #tx: MapConstructorExec<ApiType> = {};

-  constructor (api: ApiBase<ApiType>, abi: AnyJson | Abi, codeHash: string | Hash | Uint8Array, decorateMethod: DecorateMethod<ApiType>) {
+  constructor (api: ApiBase<ApiType>, abi: string | Record<string, unknown> | Abi, codeHash: string | Hash | Uint8Array, decorateMethod: DecorateMethod<ApiType>) {
    super(api, abi, decorateMethod);

    this.codeHash = this.registry.createType('Hash', codeHash);
@@ -68,3 +72,13 @@ export class Blueprint<ApiType extends ApiTypes> extends Base<ApiType> {
      );
  };
 }
+
+export function extendBlueprint <ApiType extends ApiTypes> (type: ApiType, decorateMethod: DecorateMethod<ApiType>): BlueprintConstructor<ApiType> {
+  return class extends Blueprint<ApiType> {
+    static __BlueprintType = type;
+
+    constructor (api: ApiBase<ApiType>, abi: string | Record<string, unknown> | Abi, codeHash: string | Hash | Uint8Array) {
+      super(api, abi, codeHash, decorateMethod);
+    }
+  };
+}
@@ -1,12 +1,10 @@
 // Copyright 2017-2021 @polkadot/api-contract authors & contributors
 // SPDX-License-Identifier: Apache-2.0

-import type { AnyJson } from '@polkadot/types/types';
-
 import fs from 'fs';
 import path from 'path';

-import { decorateMethodPromise } from '@polkadot/api';
+import { toPromiseMethod } from '@polkadot/api';

 import v0contractFlipper from '../../test/contracts/ink/v0/flipper.contract.json';
 import v0abiFlipper from '../../test/contracts/ink/v0/flipper.json';
@@ -19,19 +17,19 @@ const v0wasmFlipper = fs.readFileSync(path.join(__dirname, '../../test/contracts
 describe('Code', (): void => {
  it('can construct with an individual ABI/WASM combo', (): void => {
    expect(
-      () => new Code(mockApi, v0abiFlipper as AnyJson, v0wasmFlipper, decorateMethodPromise)
+      () => new Code(mockApi, v0abiFlipper as Record<string, unknown>, v0wasmFlipper, toPromiseMethod)
    ).not.toThrow();
  });

  it('can construct with an .contract ABI (v0)', (): void => {
    expect(
-      () => new Code(mockApi, v0contractFlipper as AnyJson, null, decorateMethodPromise)
+      () => new Code(mockApi, v0contractFlipper as Record<string, unknown>, null, toPromiseMethod)
    ).not.toThrow();
  });

  it.only('can construct with an .contract ABI (v1)', (): void => {
    expect(
-      () => new Code(mockApi, v1contractFlipper as AnyJson, null, decorateMethodPromise)
+      () => new Code(mockApi, v1contractFlipper as Record<string, unknown>, null, toPromiseMethod)
    ).not.toThrow();
  });
 });
@@ -4,7 +4,7 @@
 import type { SubmittableExtrinsic } from '@polkadot/api/submittable/types';
 import type { ApiTypes, DecorateMethod } from '@polkadot/api/types';
 import type { EventRecord } from '@polkadot/types/interfaces';
-import type { AnyJson, ISubmittableResult } from '@polkadot/types/types';
+import type { ISubmittableResult } from '@polkadot/types/types';
 import type { AbiConstructor, BlueprintOptions } from '../types';
 import type { MapConstructorExec } from './types';

@@ -19,6 +19,10 @@ import { Blueprint } from './Blueprint';
 import { Contract } from './Contract';
 import { createBluePrintTx, encodeSalt } from './util';

+export interface CodeConstructor<ApiType extends ApiTypes> {
+  new(api: ApiBase<ApiType>, abi: string | Record<string, unknown> | Abi, wasm: Uint8Array | string | Buffer | null | undefined): Code<ApiType>;
+}
+
 export class CodeSubmittableResult<ApiType extends ApiTypes> extends SubmittableResult {
  public readonly blueprint?: Blueprint<ApiType>;
  public readonly contract?: Contract<ApiType>;
@@ -36,7 +40,7 @@ export class Code<ApiType extends ApiTypes> extends Base<ApiType> {

  readonly #tx: MapConstructorExec<ApiType> = {};

-  constructor (api: ApiBase<ApiType>, abi: AnyJson | Abi, wasm: Uint8Array | string | Buffer | null | undefined, decorateMethod: DecorateMethod<ApiType>) {
+  constructor (api: ApiBase<ApiType>, abi: string | Record<string, unknown> | Abi, wasm: Uint8Array | string | Buffer | null | undefined, decorateMethod: DecorateMethod<ApiType>) {
    super(api, abi, decorateMethod);

    this.code = isWasm(this.abi.info.source.wasm)
@@ -78,3 +82,13 @@ export class Code<ApiType extends ApiTypes> extends Base<ApiType> {
      );
  };
 }
+
+export function extendCode <ApiType extends ApiTypes> (type: ApiType, decorateMethod: DecorateMethod<ApiType>): CodeConstructor<ApiType> {
+  return class extends Code<ApiType> {
+    static __CodeType = type;
+
+    constructor (api: ApiBase<ApiType>, abi: string | Record<string, unknown> | Abi, wasm: Uint8Array | string | Buffer | null | undefined) {
+      super(api, abi, wasm, decorateMethod);
+    }
+  };
+}
@@ -5,7 +5,7 @@ import type { SubmittableExtrinsic } from '@polkadot/api/submittable/types';
 import type { ApiTypes, DecorateMethod } from '@polkadot/api/types';
 import type { Bytes } from '@polkadot/types';
 import type { AccountId, EventRecord, Weight } from '@polkadot/types/interfaces';
-import type { AnyJson, ISubmittableResult } from '@polkadot/types/types';
+import type { ISubmittableResult } from '@polkadot/types/types';
 import type { AbiMessage, ContractCallOutcome, ContractOptions, DecodedEvent } from '../types';
 import type { ContractCallResult, ContractCallSend, ContractQuery, ContractTx, MapMessageQuery, MapMessageTx } from './types';

@@ -19,6 +19,10 @@ import { Abi } from '../Abi';
 import { applyOnEvent, extractOptions, isOptions } from '../util';
 import { Base } from './Base';

+export interface ContractConstructor<ApiType extends ApiTypes> {
+  new(api: ApiBase<ApiType>, abi: string | Record<string, unknown> | Abi, address: string | AccountId): Contract<ApiType>;
+}
+
 // As per Rust, 5 * GAS_PER_SEC
 const MAX_CALL_GAS = new BN(5_000_000_000_000).isub(BN_ONE);
 const ERROR_NO_CALL = 'Your node does not expose the contracts.call RPC. This is most probably due to a runtime configuration.';
@@ -59,7 +63,7 @@ export class Contract<ApiType extends ApiTypes> extends Base<ApiType> {

  readonly #tx: MapMessageTx<ApiType> = {};

-  constructor (api: ApiBase<ApiType>, abi: AnyJson | Abi, address: string | AccountId, decorateMethod: DecorateMethod<ApiType>) {
+  constructor (api: ApiBase<ApiType>, abi: string | Record<string, unknown> | Abi, address: string | AccountId, decorateMethod: DecorateMethod<ApiType>) {
    super(api, abi, decorateMethod);

    this.address = this.registry.createType('AccountId', address);
@@ -161,3 +165,13 @@ export class Contract<ApiType extends ApiTypes> extends Base<ApiType> {
    };
  };
 }
+
+export function extendContract <ApiType extends ApiTypes> (type: ApiType, decorateMethod: DecorateMethod<ApiType>): ContractConstructor<ApiType> {
+  return class extends Contract<ApiType> {
+    static __ContractType = type;
+
+    constructor (api: ApiBase<ApiType>, abi: string | Record<string, unknown> | Abi, address: string | AccountId) {
+      super(api, abi, address, decorateMethod);
+    }
+  };
+}
@@ -1,6 +1,6 @@
 // Copyright 2017-2021 @polkadot/api authors & contributors
 // SPDX-License-Identifier: Apache-2.0

-export { Blueprint, BlueprintSubmittableResult } from './Blueprint';
-export { Code, CodeSubmittableResult } from './Code';
-export { Contract } from './Contract';
+export { Blueprint, BlueprintSubmittableResult, extendBlueprint } from './Blueprint';
+export { Code, CodeSubmittableResult, extendCode } from './Code';
+export { Contract, extendContract } from './Contract';
@@ -3,8 +3,6 @@

 // Simple non-runnable checks to test type definitions in the editor itself

-import type { AnyJson } from '@polkadot/types/types';
-
 import { ApiPromise } from '@polkadot/api';
 import { createTestPairs, TestKeyringMap } from '@polkadot/keyring/testingPairs';

@@ -12,7 +10,7 @@ import abiIncrementer from '../test/contracts/ink/incrementer.json';
 import { BlueprintPromise, ContractPromise } from '.';

 async function checkBlueprint (api: ApiPromise, pairs: TestKeyringMap): Promise<void> {
-  const blueprint = new BlueprintPromise(api, abiIncrementer as AnyJson, '0x1234');
+  const blueprint = new BlueprintPromise(api, abiIncrementer as Record<string, unknown>, '0x1234');

  // new style
  await blueprint.tx.new({ gasLimit: 456, salt: '0x1234', value: 123 }, 42).signAndSend(pairs.bob);
@@ -23,7 +21,7 @@ async function checkBlueprint (api: ApiPromise, pairs: TestKeyringMap): Promise<
 }

 async function checkContract (api: ApiPromise, pairs: TestKeyringMap): Promise<void> {
-  const contract = new ContractPromise(api, abiIncrementer as AnyJson, '0x1234');
+  const contract = new ContractPromise(api, abiIncrementer as Record<string, unknown>, '0x1234');

  // queries
  await contract.query.get(pairs.alice.address, {});
@@ -3,4 +3,4 @@

 // Auto-generated by @polkadot/dev, do not edit

-export const packageInfo = { name: '@polkadot/api-contract', version: '6.4.1' };
+export const packageInfo = { name: '@polkadot/api-contract', version: '6.12.1' };
@@ -1,16 +0,0 @@
-// Copyright 2017-2021 @polkadot/api-contract authors & contributors
-// SPDX-License-Identifier: Apache-2.0
-
-import type { Hash } from '@polkadot/types/interfaces';
-import type { AnyJson } from '@polkadot/types/types';
-
-import { ApiPromise, decorateMethodPromise } from '@polkadot/api';
-
-import { Abi } from '../Abi';
-import { Blueprint as BaseBlueprint } from '../base';
-
-export class Blueprint extends BaseBlueprint<'promise'> {
-  constructor (api: ApiPromise, abi: AnyJson | Abi, codeHash: string | Hash) {
-    super(api, abi, codeHash, decorateMethodPromise);
-  }
-}
@@ -1,16 +0,0 @@
-// Copyright 2017-2021 @polkadot/api-contract authors & contributors
-// SPDX-License-Identifier: Apache-2.0
-
-import type { ApiPromise } from '@polkadot/api';
-import type { AnyJson } from '@polkadot/types/types';
-
-import { decorateMethodPromise } from '@polkadot/api';
-
-import { Abi } from '../Abi';
-import { Code as BaseCode } from '../base';
-
-export class Code extends BaseCode<'promise'> {
-  constructor (api: ApiPromise, abi: AnyJson | Abi, wasm: Uint8Array | string | Buffer | null | undefined) {
-    super(api, abi, wasm, decorateMethodPromise);
-  }
-}
@@ -1,16 +0,0 @@
-// Copyright 2017-2021 @polkadot/api-contract authors & contributors
-// SPDX-License-Identifier: Apache-2.0
-
-import type { AccountId } from '@polkadot/types/interfaces';
-import type { AnyJson } from '@polkadot/types/types';
-
-import { ApiPromise, decorateMethodPromise } from '@polkadot/api';
-
-import { Abi } from '../Abi';
-import { Contract as BaseContract } from '../base';
-
-export class Contract extends BaseContract<'promise'> {
-  constructor (api: ApiPromise, abi: AnyJson | Abi, address: string | AccountId) {
-    super(api, abi, address, decorateMethodPromise);
-  }
-}
@@ -1,6 +1,10 @@
 // Copyright 2017-2021 @polkadot/api-contract authors & contributors
 // SPDX-License-Identifier: Apache-2.0

-export { Blueprint } from './Blueprint';
-export { Code } from './Code';
-export { Contract } from './Contract';
+import { toPromiseMethod } from '@polkadot/api';
+
+import { extendBlueprint, extendCode, extendContract } from '../base';
+
+export const Blueprint = extendBlueprint<'promise'>('promise', toPromiseMethod);
+export const Code = extendCode<'promise'>('promise', toPromiseMethod);
+export const Contract = extendContract<'promise'>('promise', toPromiseMethod);
@@ -1,16 +0,0 @@
-// Copyright 2017-2021 @polkadot/api-contract authors & contributors
-// SPDX-License-Identifier: Apache-2.0
-
-import type { Hash } from '@polkadot/types/interfaces';
-import type { AnyJson } from '@polkadot/types/types';
-
-import { ApiRx, decorateMethodRx } from '@polkadot/api';
-
-import { Abi } from '../Abi';
-import { Blueprint as BaseBlueprint } from '../base';
-
-export class Blueprint extends BaseBlueprint<'rxjs'> {
-  constructor (api: ApiRx, abi: AnyJson | Abi, codeHash: string | Hash) {
-    super(api, abi, codeHash, decorateMethodRx);
-  }
-}
@@ -1,16 +0,0 @@
-// Copyright 2017-2021 @polkadot/api-contract authors & contributors
-// SPDX-License-Identifier: Apache-2.0
-
-import type { ApiRx } from '@polkadot/api';
-import type { AnyJson } from '@polkadot/types/types';
-
-import { decorateMethodRx } from '@polkadot/api';
-
-import { Abi } from '../Abi';
-import { Code as BaseCode } from '../base';
-
-export class Code extends BaseCode<'rxjs'> {
-  constructor (api: ApiRx, abi: AnyJson | Abi, wasm: Uint8Array | string | Buffer | null | undefined) {
-    super(api, abi, wasm, decorateMethodRx);
-  }
-}
@@ -1,16 +0,0 @@
-// Copyright 2017-2021 @polkadot/api-contract authors & contributors
-// SPDX-License-Identifier: Apache-2.0
-
-import type { AccountId } from '@polkadot/types/interfaces';
-import type { AnyJson } from '@polkadot/types/types';
-
-import { ApiRx, decorateMethodRx } from '@polkadot/api';
-
-import { Abi } from '../Abi';
-import { Contract as BaseContract } from '../base';
-
-export class Contract extends BaseContract<'rxjs'> {
-  constructor (api: ApiRx, abi: AnyJson | Abi, address: string | AccountId) {
-    super(api, abi, address, decorateMethodRx);
-  }
-}
@@ -1,6 +1,10 @@
 // Copyright 2017-2021 @polkadot/api-contract authors & contributors
 // SPDX-License-Identifier: Apache-2.0

-export { Blueprint } from './Blueprint';
-export { Code } from './Code';
-export { Contract } from './Contract';
+import { toRxMethod } from '@polkadot/api';
+
+import { extendBlueprint, extendCode, extendContract } from '../base';
+
+export const Blueprint = extendBlueprint<'rxjs'>('rxjs', toRxMethod);
+export const Code = extendCode<'rxjs'>('rxjs', toRxMethod);
+export const Contract = extendContract<'rxjs'>('rxjs', toRxMethod);
@@ -0,0 +1,204 @@
+[
+  {
+    "info": "Plain",
+    "lookupIndex": 0,
+    "type": "u128",
+    "docs": [],
+    "namespace": ""
+  },
+  {
+    "info": "Struct",
+    "lookupIndex": 1,
+    "type": "{\"offsetKey\":\"InkPrimitivesKey\"}",
+    "docs": [],
+    "namespace": "ink_storage::lazy::mapping::Mapping",
+    "sub": [
+      {
+        "info": "VecFixed",
+        "lookupIndex": 5,
+        "lookupName": "InkPrimitivesKey",
+        "type": "[u8;32]",
+        "docs": [],
+        "namespace": "",
+        "length": 32,
+        "sub": {
+          "info": "Plain",
+          "lookupIndex": 4,
+          "type": "u8",
+          "docs": [],
+          "namespace": ""
+        },
+        "typeName": "Key",
+        "name": "offsetKey"
+      }
+    ]
+  },
+  {
+    "info": "Plain",
+    "lookupIndex": 2,
+    "type": "AccountId",
+    "docs": [],
+    "namespace": "ink_env::types::AccountId",
+    "lookupNameRoot": "InkEnvAccountId"
+  },
+  {
+    "info": "VecFixed",
+    "lookupIndex": 3,
+    "type": "[u8;32]",
+    "docs": [],
+    "namespace": "",
+    "length": 32,
+    "sub": {
+      "info": "Plain",
+      "lookupIndex": 4,
+      "type": "u8",
+      "docs": [],
+      "namespace": ""
+    }
+  },
+  {
+    "info": "Plain",
+    "lookupIndex": 4,
+    "type": "u8",
+    "docs": [],
+    "namespace": ""
+  },
+  {
+    "info": "VecFixed",
+    "lookupIndex": 5,
+    "lookupName": "InkPrimitivesKey",
+    "type": "[u8;32]",
+    "docs": [],
+    "namespace": "",
+    "length": 32,
+    "sub": {
+      "info": "Plain",
+      "lookupIndex": 4,
+      "type": "u8",
+      "docs": [],
+      "namespace": ""
+    },
+    "typeName": "[u8;32]"
+  },
+  {
+    "info": "Struct",
+    "lookupIndex": 6,
+    "type": "{\"offsetKey\":\"InkPrimitivesKey\"}",
+    "docs": [],
+    "namespace": "ink_storage::lazy::mapping::Mapping",
+    "sub": [
+      {
+        "info": "VecFixed",
+        "lookupIndex": 5,
+        "lookupName": "InkPrimitivesKey",
+        "type": "[u8;32]",
+        "docs": [],
+        "namespace": "",
+        "length": 32,
+        "sub": {
+          "info": "Plain",
+          "lookupIndex": 4,
+          "type": "u8",
+          "docs": [],
+          "namespace": ""
+        },
+        "typeName": "Key",
+        "name": "offsetKey"
+      }
+    ]
+  },
+  {
+    "info": "Tuple",
+    "lookupIndex": 7,
+    "type": "(AccountId,AccountId)",
+    "docs": [],
+    "namespace": "",
+    "sub": [
+      {
+        "info": "Plain",
+        "lookupIndex": 2,
+        "type": "AccountId",
+        "docs": [],
+        "namespace": "ink_env::types::AccountId",
+        "lookupNameRoot": "InkEnvAccountId"
+      },
+      {
+        "info": "Plain",
+        "lookupIndex": 2,
+        "type": "AccountId",
+        "docs": [],
+        "namespace": "ink_env::types::AccountId",
+        "lookupNameRoot": "InkEnvAccountId"
+      }
+    ]
+  },
+  {
+    "info": "Result",
+    "lookupIndex": 8,
+    "type": "Result<Null, Erc20Error>",
+    "docs": [],
+    "namespace": "Result",
+    "sub": [
+      {
+        "name": "Ok",
+        "info": "Null",
+        "lookupIndex": 9,
+        "type": "Null",
+        "docs": [],
+        "namespace": ""
+      },
+      {
+        "name": "Error",
+        "docs": [],
+        "info": "Si",
+        "lookupIndex": 10,
+        "lookupName": "Erc20Error",
+        "type": "Lookup10"
+      }
+    ]
+  },
+  {
+    "info": "Null",
+    "lookupIndex": 9,
+    "type": "Null",
+    "docs": [],
+    "namespace": ""
+  },
+  {
+    "info": "Enum",
+    "lookupIndex": 10,
+    "lookupName": "Erc20Error",
+    "type": "{\"_enum\":[\"InsufficientBalance\",\"InsufficientAllowance\"]}",
+    "docs": [],
+    "namespace": "erc20::erc20::Error",
+    "sub": [
+      {
+        "info": "Null",
+        "type": "Null",
+        "index": 0,
+        "name": "InsufficientBalance"
+      },
+      {
+        "info": "Null",
+        "type": "Null",
+        "index": 1,
+        "name": "InsufficientAllowance"
+      }
+    ]
+  },
+  {
+    "info": "Option",
+    "lookupIndex": 11,
+    "type": "Option<AccountId>",
+    "docs": [],
+    "namespace": "Option",
+    "sub": {
+      "info": "Plain",
+      "lookupIndex": 2,
+      "type": "AccountId",
+      "docs": [],
+      "namespace": "ink_env::types::AccountId",
+      "lookupNameRoot": "InkEnvAccountId"
+    }
+  }
+]
@@ -0,0 +1,9 @@
+[
+  {
+    "info": "Plain",
+    "lookupIndex": 0,
+    "type": "bool",
+    "docs": [],
+    "namespace": ""
+  }
+]
@@ -18,6 +18,7 @@
        "lookupIndex": 1,
        "lookupName": "RecursiveMyEnum",
        "type": "Lookup1",
+        "typeName": "MyEnum",
        "index": 1,
        "name": "B"
      }
@@ -5,17 +5,12 @@ import ink from './ink';
 import solang from './solang';
 import user from './user';

-const all: Record<string, any> = {};
+const all: Record<string, Record<string, unknown>> = {};

-function addExport (type: string, abis: Record<string, any>): void {
-  Object.keys(abis).forEach((key): void => {
-    // eslint-disable-next-line @typescript-eslint/no-unsafe-assignment
-    all[`${type}_${key}`] = abis[key];
-  });
-}
-
-addExport('ink', ink);
-addExport('solang', solang);
-addExport('user', user);
+Object.entries({ ink, solang, user }).forEach(([type, abis]) =>
+  Object.entries(abis).forEach(([name, abi]): void => {
+    all[`${type}_${name}`] = abi;
+  })
+);

 export default all;
@@ -4,7 +4,6 @@
 import { createVersionedExport } from '../util';
 import * as v0 from './v0';
 import * as v1 from './v1';
+import * as v2 from './v2';

-const exp = createVersionedExport('v0', v0, {});
-
-export default createVersionedExport('v1', v1, exp);
+export default createVersionedExport({ v0, v1, v2 });
@@ -0,0 +1,5 @@
+// Copyright 2017-2021 @polkadot/api-contract authors & contributors
+// SPDX-License-Identifier: Apache-2.0
+
+export { default as erc20 } from './erc20.contract.json';
+export { default as flipper } from './flipper.contract.json';
@@ -4,4 +4,4 @@
 import { createVersionedExport } from '../util';
 import * as v0 from './v0';

-export default createVersionedExport('v0', v0, {});
+export default createVersionedExport({ v0 });
@@ -4,4 +4,4 @@
 import { createVersionedExport } from '../util';
 import * as v0 from './v0';

-export default createVersionedExport('v0', v0, {});
+export default createVersionedExport({ v0 });
@@ -1,10 +1,14 @@
 // Copyright 2017-2021 @polkadot/api-contract authors & contributors
 // SPDX-License-Identifier: Apache-2.0

-export function createVersionedExport (version: string, orig: Record<string, unknown>, exp: Record<string, unknown>): Record<string, unknown> {
-  Object.entries(orig).forEach(([name, json]): void => {
-    exp[`${version}_${name}`] = json;
-  });
+export function createVersionedExport (versioned: Record<string, Record<string, unknown>>): Record<string, Record<string, unknown>> {
+  const result: Record<string, Record<string, unknown>> = {};

-  return exp;
+  Object.entries(versioned).forEach(([version, contracts]) =>
+    Object.entries(contracts).forEach(([name, contract]): void => {
+      result[`${version}_${name}`] = contract as Record<string, unknown>;
+    })
+  );
+
+  return result;
 }
@@ -1,34 +1,38 @@
 {
-  "name": "@polkadot/api-derive",
-  "version": "6.4.1",
-  "type": "module",
+  "author": "Jaco Greeff <jacogr@gmail.com>",
+  "bugs": "https://github.com/polkadot-js/api/issues",
+  "contributors": [],
  "description": "Common functions used across Polkadot, derived from RPC calls and storage queries.",
-  "main": "index.js",
+  "engines": {
+    "node": ">=14.0.0"
+  },
+  "homepage": "https://github.com/polkadot-js/api/tree/master/packages/api-derive#readme",
+  "license": "Apache-2.0",
+  "maintainers": [],
+  "name": "@polkadot/api-derive",
+  "repository": {
+    "directory": "packages/api-derive",
+    "type": "git",
+    "url": "https://github.com/polkadot-js/api.git"
+  },
  "sideEffects": [
    "./detectPackage.js",
    "./detectPackage.cjs"
  ],
-  "engines": {
-    "node": ">=14.0.0"
-  },
-  "author": "Jaco Greeff <jacogr@gmail.com>",
-  "maintainers": [],
-  "contributors": [],
-  "license": "Apache-2.0",
-  "repository": "github:polkadot-js/api",
-  "bugs": "https://github.com/polkadot-js/api/issues",
-  "homepage": "https://github.com/polkadot-js/api/tree/master/packages/api-derive#readme",
+  "type": "module",
+  "version": "6.12.1",
+  "main": "index.js",
  "dependencies": {
-    "@babel/runtime": "^7.15.4",
-    "@polkadot/api": "6.4.1",
-    "@polkadot/rpc-core": "6.4.1",
-    "@polkadot/types": "6.4.1",
-    "@polkadot/util": "^7.5.1",
-    "@polkadot/util-crypto": "^7.5.1",
+    "@babel/runtime": "^7.16.3",
+    "@polkadot/api": "6.12.1",
+    "@polkadot/rpc-core": "6.12.1",
+    "@polkadot/types": "6.12.1",
+    "@polkadot/util": "^8.1.2",
+    "@polkadot/util-crypto": "^8.1.2",
    "rxjs": "^7.4.0"
  },
  "devDependencies": {
-    "@polkadot/keyring": "^7.5.1",
-    "@polkadot/rpc-provider": "6.4.1"
+    "@polkadot/keyring": "^8.1.2",
+    "@polkadot/rpc-provider": "6.12.1"
  }
 }
@@ -12,28 +12,25 @@ import { decodeAddress } from '@polkadot/util-crypto';

 import { memo } from '../util';

-function retrieve (api: ApiInterfaceRx, address: Address | AccountId | AccountIndex | string | null | undefined): Observable<AccountId> {
-  const decoded = isU8a(address)
-    ? address
-    : decodeAddress((address || '').toString());
-
-  if (decoded.length > 8) {
-    return of(api.registry.createType('AccountId', decoded));
-  }
-
-  const accountIndex = api.registry.createType('AccountIndex', decoded);
-
-  return api.derive.accounts.indexToId(accountIndex.toString()).pipe(
-    map((accountId) => assertReturn(accountId, 'Unable to retrieve accountId'))
-  );
-}
-
 /**
 * @name accountId
 * @param {(Address | AccountId | AccountIndex | string | null)} address - An accounts address in various formats.
 * @description  An [[AccountId]]
 */
 export function accountId (instanceId: string, api: ApiInterfaceRx): (address?: Address | AccountId | AccountIndex | string | null) => Observable<AccountId> {
-  return memo(instanceId, (address?: Address | AccountId | AccountIndex | string | null): Observable<AccountId> =>
-    retrieve(api, address));
+  return memo(instanceId, (address?: Address | AccountId | AccountIndex | string | null): Observable<AccountId> => {
+    const decoded = isU8a(address)
+      ? address
+      : decodeAddress((address || '').toString());
+
+    if (decoded.length > 8) {
+      return of(api.registry.createType('AccountId', decoded));
+    }
+
+    const accountIndex = api.registry.createType('AccountIndex', decoded);
+
+    return api.derive.accounts.indexToId(accountIndex.toString()).pipe(
+      map((a) => assertReturn(a, 'Unable to retrieve accountId'))
+    );
+  });
 }
@@ -40,15 +40,11 @@ function parseFlags (address: AccountId | Address | string | null | undefined, [
 */
 export function flags (instanceId: string, api: ApiInterfaceRx): (address?: AccountId | Address | string | null) => Observable<DeriveAccountFlags> {
  return memo(instanceId, (address?: AccountId | Address | string | null): Observable<DeriveAccountFlags> => {
-    const councilSection = api.query.phragmenElection
-      ? 'phragmenElection'
-      : api.query.electionsPhragmen
-        ? 'electionsPhragmen'
-        : 'elections';
+    const elections = api.query.phragmenElection || api.query.electionsPhragmen || api.query.elections;

    return combineLatest([
-      address && api.query[councilSection]?.members
-        ? api.query[councilSection].members<Vec<ITuple<[AccountId, Balance]>>>()
+      address && elections?.members
+        ? elections.members<Vec<ITuple<[AccountId, Balance]>>>()
        : of(undefined),
      address && api.query.council?.members
        ? api.query.council.members()
@@ -63,7 +59,7 @@ export function flags (instanceId: string, api: ApiInterfaceRx): (address?: Acco
        ? api.query.sudo.key()
        : of(undefined)
    ]).pipe(
-      map((result) => parseFlags(address, result))
+      map((r) => parseFlags(address, r))
    );
  });
 }
@@ -13,31 +13,6 @@ import { decodeAddress } from '@polkadot/util-crypto';

 import { memo } from '../util';

-function retrieve (api: ApiInterfaceRx, address: Address | AccountId | AccountIndex | Uint8Array | string | null | undefined): Observable<AccountIdAndIndex> {
-  try {
-    // yes, this can fail, don't care too much, catch will catch it
-    const decoded = isU8a(address)
-      ? address
-      : decodeAddress((address || '').toString());
-
-    if (decoded.length > 8) {
-      const accountId = api.registry.createType('AccountId', decoded);
-
-      return api.derive.accounts.idToIndex(accountId).pipe(
-        map((accountIndex): AccountIdAndIndex => [accountId, accountIndex])
-      );
-    }
-
-    const accountIndex = api.registry.createType('AccountIndex', decoded);
-
-    return api.derive.accounts.indexToId(accountIndex.toString()).pipe(
-      map((accountId): AccountIdAndIndex => [accountId, accountIndex])
-    );
-  } catch (error) {
-    return of([undefined, undefined]);
-  }
-}
-
 /**
 * @name idAndIndex
 * @param {(Address | AccountId | AccountIndex | Uint8Array | string | null)} address - An accounts address in various formats.
@@ -52,6 +27,28 @@ function retrieve (api: ApiInterfaceRx, address: Address | AccountId | AccountIn
 * ```
 */
 export function idAndIndex (instanceId: string, api: ApiInterfaceRx): (address?: Address | AccountId | AccountIndex | Uint8Array | string | null) => Observable<AccountIdAndIndex> {
-  return memo(instanceId, (address?: Address | AccountId | AccountIndex | Uint8Array | string | null): Observable<AccountIdAndIndex> =>
-    retrieve(api, address));
+  return memo(instanceId, (address?: Address | AccountId | AccountIndex | Uint8Array | string | null): Observable<AccountIdAndIndex> => {
+    try {
+      // yes, this can fail, don't care too much, catch will catch it
+      const decoded = isU8a(address)
+        ? address
+        : decodeAddress((address || '').toString());
+
+      if (decoded.length > 8) {
+        const accountId = api.registry.createType('AccountId', decoded);
+
+        return api.derive.accounts.idToIndex(accountId).pipe(
+          map((accountIndex): AccountIdAndIndex => [accountId, accountIndex])
+        );
+      }
+
+      const accountIndex = api.registry.createType('AccountIndex', decoded);
+
+      return api.derive.accounts.indexToId(accountIndex.toString()).pipe(
+        map((accountId): AccountIdAndIndex => [accountId, accountIndex])
+      );
+    } catch (error) {
+      return of([undefined, undefined]);
+    }
+  });
 }
@@ -13,7 +13,7 @@ import { combineLatest, map, of, switchMap } from 'rxjs';

 import { isHex, u8aToString } from '@polkadot/util';

-import { memo } from '../util';
+import { firstMemo, memo } from '../util';

 type IdentityInfoAdditional = PalletIdentityIdentityInfo['additional'][0];

@@ -104,13 +104,10 @@ export function identity (instanceId: string, api: ApiInterfaceRx): (accountId?:
  );
 }

-export function hasIdentity (instanceId: string, api: ApiInterfaceRx): (accountId: AccountId | Uint8Array | string) => Observable<DeriveHasIdentity> {
-  return memo(instanceId, (accountId: AccountId | Uint8Array | string): Observable<DeriveHasIdentity> =>
-    api.derive.accounts.hasIdentityMulti([accountId]).pipe(
-      map(([first]) => first)
-    )
-  );
-}
+export const hasIdentity = firstMemo(
+  (api: ApiInterfaceRx, accountId: AccountId | Uint8Array | string) =>
+    api.derive.accounts.hasIdentityMulti([accountId])
+);

 export function hasIdentityMulti (instanceId: string, api: ApiInterfaceRx): (accountIds: (AccountId | Uint8Array | string)[]) => Observable<DeriveHasIdentity[]> {
  return memo(instanceId, (accountIds: (AccountId | Uint8Array | string)[]): Observable<DeriveHasIdentity[]> =>
@@ -165,9 +165,7 @@ function queryCurrent (api: ApiInterfaceRx, accountId: AccountId, balanceInstanc

      return [
        vesting
-          ? Array.isArray(vesting)
-            ? vesting
-            : [vesting]
+          ? Array.isArray(vesting) ? vesting : [vesting]
          : null,
        lockEmpty.map((e) => e ? api.registry.createType<Vec<PalletBalancesBalanceLock>>('Vec<BalanceLock>') : locks[++offset])
      ];
@@ -42,14 +42,12 @@ export function bounties (instanceId: string, api: ApiInterfaceRx): () => Observ
        ? api.query.council.proposalCount<ProposalIndex>()
        : of(0)
    ]).pipe(
-      switchMap(() =>
-        combineLatest([
-          bountyBase.bounties.keys<[BountyIndex]>(),
-          api.derive.council
-            ? api.derive.council.proposals()
-            : of([])
-        ])
-      ),
+      switchMap(() => combineLatest([
+        bountyBase.bounties.keys<[BountyIndex]>(),
+        api.derive.council
+          ? api.derive.council.proposals()
+          : of([])
+      ])),
      switchMap(([keys, proposals]): Observable<Result> => {
        const ids = keys.map(({ args: [id] }) => id);

@@ -5,6 +5,7 @@ import type { Observable } from 'rxjs';
 import type { ApiInterfaceRx } from '@polkadot/api/types';
 import type { AnyFunction } from '@polkadot/types/types';

+import { lazyDeriveSection } from './util/lazy';
 import * as accounts from './accounts';
 import * as balances from './balances';
 import * as bounties from './bounties';
@@ -29,18 +30,21 @@ export * from './type';

 interface Avail {
  instances: string[];
+  methods: string[];
  withDetect?: boolean;
 }

+export { lazyDeriveSection };
+
 export const derive = { accounts, balances, bounties, chain, contracts, council, crowdloan, democracy, elections, imOnline, membership, parachains, session, society, staking, technicalCommittee, treasury, tx };

 type DeriveSection<Section> = {
-  [Method in keyof Section]: Section[Method] extends AnyFunction
-    ? ReturnType<Section[Method]> // ReturnType<Section[Method]> will be the inner function, i.e. without (api) argument
+  [M in keyof Section]: Section[M] extends AnyFunction
+    ? ReturnType<Section[M]> // ReturnType<Section[Method]> will be the inner function, i.e. without (api) argument
    : never;
 };
 type DeriveAllSections<AllSections> = {
-  [Section in keyof AllSections]: DeriveSection<AllSections[Section]>
+  [S in keyof AllSections]: DeriveSection<AllSections[S]>
 };

 type DeriveCreator = (instanceId: string, api: ApiInterfaceRx) => (...args: unknown[]) => Observable<any>;
@@ -51,64 +55,110 @@ export type ExactDerive = DeriveAllSections<typeof derive>;

 // Enable derive only if some of these modules are available
 const checks: Record<string, Avail> = {
-  contracts: { instances: ['contracts'] },
-  council: { instances: ['council'], withDetect: true },
-  crowdloan: { instances: ['crowdloan'] },
-  democracy: { instances: ['democracy'] },
-  elections: { instances: ['phragmenElection', 'electionsPhragmen', 'elections', 'council'], withDetect: true },
-  imOnline: { instances: ['imOnline'] },
-  membership: { instances: ['membership'] },
-  parachains: { instances: ['parachains', 'registrar'] },
-  session: { instances: ['session'] },
-  society: { instances: ['society'] },
-  staking: { instances: ['staking'] },
-  technicalCommittee: { instances: ['technicalCommittee'], withDetect: true },
-  treasury: { instances: ['treasury'] }
+  contracts: {
+    instances: ['contracts'],
+    methods: []
+  },
+  council: {
+    instances: ['council'],
+    methods: [],
+    withDetect: true
+  },
+  crowdloan: {
+    instances: ['crowdloan'],
+    methods: []
+  },
+  democracy: {
+    instances: ['democracy'],
+    methods: []
+  },
+  elections: {
+    instances: ['phragmenElection', 'electionsPhragmen', 'elections', 'council'],
+    methods: [],
+    withDetect: true
+  },
+  imOnline: {
+    instances: ['imOnline'],
+    methods: []
+  },
+  membership: {
+    instances: ['membership'],
+    methods: []
+  },
+  parachains: {
+    instances: ['parachains', 'registrar'],
+    methods: []
+  },
+  session: {
+    instances: ['session'],
+    methods: []
+  },
+  society: {
+    instances: ['society'],
+    methods: []
+  },
+  staking: {
+    instances: ['staking'],
+    methods: ['erasRewardPoints']
+  },
+  technicalCommittee: {
+    instances: ['technicalCommittee'],
+    methods: [],
+    withDetect: true
+  },
+  treasury: {
+    instances: ['treasury'],
+    methods: []
+  }
 };

+function getModuleInstances (api: ApiInterfaceRx, specName: string, moduleName: string): string[] {
+  return api.registry.getModuleInstances(specName, moduleName) || [];
+}
+
 /**
 * Returns an object that will inject `api` into all the functions inside
 * `allSections`, and keep the object architecture of `allSections`.
 */
 /** @internal */
-function injectFunctions<AllSections> (instanceId: string, api: ApiInterfaceRx, allSections: AllSections): DeriveAllSections<AllSections> {
-  const queryKeys = Object.keys(api.query);
+function injectFunctions (instanceId: string, api: ApiInterfaceRx, derives: DeriveCustom): ExactDerive {
+  const result: Record<string, Record<string, AnyFunction>> = {};
+  const names = Object.keys(derives);
+  const keys = Object.keys(api.query);
  const specName = api.runtimeVersion.specName.toString();

-  return Object
-    .keys(allSections)
-    .filter((sectionName) =>
-      !checks[sectionName] ||
-      checks[sectionName].instances.some((q) => queryKeys.includes(q)) ||
-      (
-        checks[sectionName].withDetect &&
-        checks[sectionName].instances.some((q) =>
-          (api.registry.getModuleInstances(specName, q) || []).some((q) => queryKeys.includes(q))
-        )
-      )
+  const filterKeys = (q: string) => keys.includes(q);
+  const filterInstances = (q: string) => getModuleInstances(api, specName, q).some(filterKeys);
+  const filterMethods = (all: string[]) => (m: string) => all.some((q) => keys.includes(q) && api.query[q][m]);
+  const getKeys = (s: string) => Object.keys(derives[s]);
+  const creator = (s: string, m: string) => derives[s][m](instanceId, api);
+  const isIncluded = (c: string) => (!checks[c] || (
+    (checks[c].instances.some(filterKeys) && (
+      !checks[c].methods.length ||
+      checks[c].methods.every(filterMethods(checks[c].instances))
+    )) ||
+    (
+      checks[c].withDetect &&
+      checks[c].instances.some(filterInstances)
    )
-    .reduce((derives, sectionName): DeriveAllSections<AllSections> => {
-      const section = allSections[sectionName as keyof AllSections];
+  ));

-      derives[sectionName as keyof AllSections] = Object
-        .entries(section)
-        .reduce((methods, [methodName, creator]): DeriveSection<typeof section> => {
-          // eslint-disable-next-line @typescript-eslint/no-unsafe-assignment,@typescript-eslint/no-unsafe-call
-          methods[methodName as keyof typeof section] = creator(instanceId, api);
+  for (let i = 0; i < names.length; i++) {
+    const name = names[i];

-          return methods;
-        }, {} as DeriveSection<typeof section>);
+    isIncluded(name) &&
+      lazyDeriveSection(result, name, getKeys, creator);
+  }

-      return derives;
-    }, {} as DeriveAllSections<AllSections>);
+  return result as ExactDerive;
 }

 // FIXME The return type of this function should be {...ExactDerive, ...DeriveCustom}
 // For now we just drop the custom derive typings
 /** @internal */
-export function decorateDerive (instanceId: string, api: ApiInterfaceRx, custom: DeriveCustom = {}): ExactDerive {
+export function getAvailableDerives (instanceId: string, api: ApiInterfaceRx, custom: DeriveCustom = {}): ExactDerive {
  return {
-    ...injectFunctions(instanceId, api, derive),
+    ...injectFunctions(instanceId, api, derive as DeriveCustom),
    ...injectFunctions(instanceId, api, custom)
  };
 }
@@ -1,13 +1,9 @@
 // Copyright 2017-2021 @polkadot/api-derive authors & contributors
 // SPDX-License-Identifier: Apache-2.0

-import type { Observable } from 'rxjs';
 import type { ApiInterfaceRx } from '@polkadot/api/types';
-import type { BlockNumber } from '@polkadot/types/interfaces';

-import { map } from 'rxjs';
-
-import { memo } from '../util';
+import { unwrapBlockNumber } from './util';

 /**
 * @name bestNumber
@@ -21,9 +17,7 @@ import { memo } from '../util';
 * });
 * ```
 */
-export function bestNumber (instanceId: string, api: ApiInterfaceRx): () => Observable<BlockNumber> {
-  return memo(instanceId, (): Observable<BlockNumber> =>
-    api.derive.chain.subscribeNewHeads().pipe(
-      map((header) => header.number.unwrap())
-    ));
-}
+export const bestNumber = unwrapBlockNumber(
+  (api: ApiInterfaceRx) =>
+    api.derive.chain.subscribeNewHeads()
+);
@@ -1,13 +1,9 @@
 // Copyright 2017-2021 @polkadot/api-derive authors & contributors
 // SPDX-License-Identifier: Apache-2.0

-import type { Observable } from 'rxjs';
 import type { ApiInterfaceRx } from '@polkadot/api/types';
-import type { BlockNumber } from '@polkadot/types/interfaces';

-import { map } from 'rxjs';
-
-import { memo } from '../util';
+import { unwrapBlockNumber } from './util';

 /**
 * @name bestNumberFinalized
@@ -22,9 +18,7 @@ import { memo } from '../util';
 * });
 * ```
 */
-export function bestNumberFinalized (instanceId: string, api: ApiInterfaceRx): () => Observable<BlockNumber> {
-  return memo(instanceId, (): Observable<BlockNumber> =>
-    api.rpc.chain.subscribeFinalizedHeads().pipe(
-      map((header) => header.number.unwrap())
-    ));
-}
+export const bestNumberFinalized = unwrapBlockNumber(
+  (api: ApiInterfaceRx) =>
+    api.rpc.chain.subscribeFinalizedHeads()
+);
@@ -25,17 +25,20 @@ import { memo } from '../util';
 */
 export function getBlock (instanceId: string, api: ApiInterfaceRx): (hash: Uint8Array | string) => Observable<SignedBlockExtended | undefined> {
  return memo(instanceId, (blockHash: Uint8Array | string): Observable<SignedBlockExtended | undefined> =>
-    api.queryAt(blockHash).pipe(
-      switchMap((queryAt) =>
-        combineLatest([
-          api.rpc.chain.getBlock(blockHash),
-          queryAt.system.events(),
-          queryAt.session
-            ? queryAt.session.validators()
-            : of([])
-        ])
-      ),
-      map(([signedBlock, events, validators]) =>
+    combineLatest([
+      api.rpc.chain.getBlock(blockHash),
+      api.queryAt(blockHash).pipe(
+        switchMap((queryAt) =>
+          combineLatest([
+            queryAt.system.events(),
+            queryAt.session
+              ? queryAt.session.validators()
+              : of([])
+          ])
+        )
+      )
+    ]).pipe(
+      map(([signedBlock, [events, validators]]) =>
        createSignedBlockExtended(api.registry, signedBlock, events, validators)
      ),
      catchError((): Observable<undefined> =>
@@ -25,17 +25,18 @@ import { memo } from '../util';
 * console.log(`block #${number} was authored by ${author}`);
 * ```
 */
-export function getHeader (instanceId: string, api: ApiInterfaceRx): (hash: Uint8Array | string) => Observable<HeaderExtended | undefined> {
-  return memo(instanceId, (hash: Uint8Array | string): Observable<HeaderExtended | undefined> =>
-    api.queryAt(hash).pipe(
-      switchMap((queryAt) =>
-        combineLatest([
-          api.rpc.chain.getHeader(hash),
+export function getHeader (instanceId: string, api: ApiInterfaceRx): (blockHash: Uint8Array | string) => Observable<HeaderExtended | undefined> {
+  return memo(instanceId, (blockHash: Uint8Array | string): Observable<HeaderExtended | undefined> =>
+    combineLatest([
+      api.rpc.chain.getHeader(blockHash),
+      api.queryAt(blockHash).pipe(
+        switchMap((queryAt) =>
          queryAt.session
            ? queryAt.session.validators()
            : of([] as AccountId[])
-        ])
-      ),
+        )
+      )
+    ]).pipe(
      map(([header, validators]) =>
        createHeaderExtended(header.registry, header, validators)
      ),
@@ -21,15 +21,15 @@ export function subscribeNewBlocks (instanceId: string, api: ApiInterfaceRx): ()
        const blockHash = header.createdAtHash || header.hash;

        // we get the block first, setting up the registry
-        return api.queryAt(blockHash).pipe(
-          switchMap((queryAt) =>
-            combineLatest([
-              of(header),
-              api.rpc.chain.getBlock(blockHash),
+        return combineLatest([
+          of(header),
+          api.rpc.chain.getBlock(blockHash),
+          api.queryAt(blockHash).pipe(
+            switchMap((queryAt) =>
              queryAt.system.events()
-            ])
+            )
          )
-        );
+        ]);
      }),
      map(([header, block, events]) =>
        createSignedBlockExtended(block.registry, block, events, header.validators)
@@ -0,0 +1,23 @@
+// Copyright 2017-2021 @polkadot/api-derive authors & contributors
+// SPDX-License-Identifier: Apache-2.0
+
+import type { Observable } from 'rxjs';
+import type { ApiInterfaceRx } from '@polkadot/api/types';
+import type { Compact } from '@polkadot/types';
+import type { BlockNumber } from '@polkadot/types/interfaces';
+
+import { map } from 'rxjs';
+
+import { memo } from '../util';
+
+// re-export these - since these needs to be resolvable from api-derive, i.e. without this
+// we would emit code with ../<somewhere>/src embedded in the *.d.ts files
+export type { ApiInterfaceRx } from '@polkadot/api/types';
+export type { BlockNumber } from '@polkadot/types/interfaces';
+
+export function unwrapBlockNumber <T extends { number: Compact<BlockNumber> }> (fn: (api: ApiInterfaceRx) => Observable<T>): (instanceId: string, api: ApiInterfaceRx) => () => Observable<BlockNumber> {
+  return (instanceId: string, api: ApiInterfaceRx) =>
+    memo(instanceId, () => fn(api).pipe(
+      map((r) => r.number.unwrap())
+    ));
+}
@@ -1,12 +0,0 @@
-// Copyright 2017-2021 @polkadot/api-derive authors & contributors
-// SPDX-License-Identifier: Apache-2.0
-
-import type { ApiInterfaceRx } from '@polkadot/api/types';
-
-export function getInstance (api: ApiInterfaceRx, section: string): string {
-  const instances = api.registry.getModuleInstances(api.runtimeVersion.specName.toString(), section);
-
-  return instances && instances.length
-    ? instances[0]
-    : section;
-}
@@ -0,0 +1,38 @@
+// Copyright 2017-2021 @polkadot/api-derive authors & contributors
+// SPDX-License-Identifier: Apache-2.0
+
+import type { Observable } from 'rxjs';
+import type { ApiInterfaceRx } from '@polkadot/api/types';
+import type { Collective } from './types';
+
+import { of } from 'rxjs';
+
+import { isFunction } from '@polkadot/util';
+
+import { memo } from '../util';
+
+// We are re-exporting these from here to ensure that *.d.ts generation is correct
+export type { ApiInterfaceRx } from '@polkadot/api/types';
+
+export function getInstance (api: ApiInterfaceRx, section: string): string {
+  const instances = api.registry.getModuleInstances(api.runtimeVersion.specName.toString(), section);
+
+  return instances && instances.length
+    ? instances[0]
+    : section;
+}
+
+export function withSection <T, F extends (...args: any[]) => Observable<T>> (_section: Collective, fn: (section: string, api: ApiInterfaceRx, instanceId: string) => F): (instanceId: string, api: ApiInterfaceRx) => F {
+  return (instanceId: string, api: ApiInterfaceRx) =>
+    memo(instanceId, fn(getInstance(api, _section), api, instanceId)) as unknown as F;
+}
+
+export function callMethod <T> (method: 'members' | 'proposals' | 'proposalCount', empty: T): (_section: Collective) => (instanceId: string, api: ApiInterfaceRx) => () => Observable<T> {
+  return (_section: Collective) =>
+    withSection(_section, (section, api) =>
+      (): Observable<T> =>
+        isFunction(api.query[section]?.[method])
+          ? api.query[section as 'council'][method]() as unknown as Observable<T>
+          : of(empty)
+    );
+}
@@ -1,24 +1,11 @@
 // Copyright 2017-2021 @polkadot/api-derive authors & contributors
 // SPDX-License-Identifier: Apache-2.0

-import type { Observable } from 'rxjs';
-import type { ApiInterfaceRx } from '@polkadot/api/types';
 import type { AccountId } from '@polkadot/types/interfaces';
-import type { Collective } from './types';

-import { of } from 'rxjs';
+import { callMethod } from './helpers';

-import { isFunction } from '@polkadot/util';
+// We are re-exporting these from here to ensure that *.d.ts generation is correct
+export type { AccountId } from '@polkadot/types/interfaces';

-import { memo } from '../util';
-import { getInstance } from './getInstance';
-
-export function members (instanceId: string, api: ApiInterfaceRx, _section: Collective): () => Observable<AccountId[]> {
-  const section = getInstance(api, _section);
-
-  return memo(instanceId, (): Observable<AccountId[]> =>
-    isFunction(api.query[section]?.members)
-      ? api.query[section as 'council'].members()
-      : of([])
-  );
-}
+export const members = callMethod<AccountId[]>('members', []);
@@ -5,24 +5,27 @@ import type { Observable } from 'rxjs';
 import type { ApiInterfaceRx } from '@polkadot/api/types';
 import type { Option } from '@polkadot/types';
 import type { AccountId } from '@polkadot/types/interfaces';
+import type { Collective } from './types';

 import { map, of } from 'rxjs';

 import { isFunction } from '@polkadot/util';

-import { memo } from '../util';
-import { getInstance } from './getInstance';
+import { withSection } from './helpers';

-export function prime (instanceId: string, api: ApiInterfaceRx, _section: string): () => Observable<AccountId | null> {
-  const section = getInstance(api, _section);
+// We are re-exporting these from here to ensure that *.d.ts generation is correct
+export type { ApiInterfaceRx } from '@polkadot/api/types';
+export type { AccountId } from '@polkadot/types/interfaces';

-  return memo(instanceId, (): Observable<AccountId | null> =>
-    isFunction(api.query[section as 'council']?.prime)
-      ? api.query[section as 'council'].prime<Option<AccountId>>().pipe(
-        map((optPrime): AccountId | null =>
-          optPrime.unwrapOr(null)
+export function prime (_section: Collective): (instanceId: string, api: ApiInterfaceRx) => () => Observable<AccountId | null> {
+  return withSection(_section, (section, api) =>
+    (): Observable<AccountId | null> =>
+      isFunction(api.query[section as 'council']?.prime)
+        ? api.query[section as 'council'].prime<Option<AccountId>>().pipe(
+          map((optPrime): AccountId | null =>
+            optPrime.unwrapOr(null)
+          )
        )
-      )
-      : of(null)
+        : of(null)
  );
 }
@@ -12,18 +12,23 @@ import { catchError, combineLatest, map, of, switchMap } from 'rxjs';

 import { isFunction } from '@polkadot/util';

-import { memo } from '../util';
-import { getInstance } from './getInstance';
+import { firstObservable } from '../util';
+import { callMethod, withSection } from './helpers';
+
+// We are re-exporting these from here to ensure that *.d.ts generation is correct
+export type { ApiInterfaceRx } from '@polkadot/api/types';
+export type { Option, u32 } from '@polkadot/types';
+export type { Hash, Proposal, Votes } from '@polkadot/types/interfaces';

 type Result = [(Hash | Uint8Array | string)[], (Option<Proposal> | null)[], Option<Votes>[]];

 function parse (api: ApiInterfaceRx, [hashes, proposals, votes]: Result): DeriveCollectiveProposal[] {
  return proposals
-    .map((proposalOpt, index): DeriveCollectiveProposal | null =>
-      proposalOpt && proposalOpt.isSome
+    .map((o, index): DeriveCollectiveProposal | null =>
+      o && o.isSome
        ? {
          hash: api.registry.createType('Hash', hashes[index]),
-          proposal: proposalOpt.unwrap(),
+          proposal: o.unwrap(),
          votes: votes[index].unwrapOr(null)
        }
        : null
@@ -31,77 +36,50 @@ function parse (api: ApiInterfaceRx, [hashes, proposals, votes]: Result): Derive
    .filter((proposal): proposal is DeriveCollectiveProposal => !!proposal);
 }

-function _proposalsFrom (instanceId: string, api: ApiInterfaceRx, section: string): (hashes: (Hash | Uint8Array | string)[]) => Observable<DeriveCollectiveProposal[]> {
-  return memo(instanceId, (hashes: (Hash | Uint8Array | string)[]): Observable<DeriveCollectiveProposal[]> =>
-    (isFunction(api.query[section]?.proposals) && hashes.length
-      ? combineLatest([
-        of(hashes),
-        // this should simply be api.query[section].proposalOf.multi<Option<Proposal>>(hashes),
-        // however we have had cases on Edgeware where the indices have moved around after an
-        // upgrade, which results in invalid on-chain data
-        combineLatest(hashes.map((hash) =>
-          api.query[section].proposalOf<Option<Proposal>>(hash).pipe(
-            catchError(() => of(null))
-          )
-        )),
-        api.query[section].voting.multi<Option<Votes>>(hashes)
-      ])
-      : of<Result>([[], [], []])
-    ).pipe(
-      map((result) => parse(api, result))
-    )
+function _proposalsFrom (section: string, api: ApiInterfaceRx, hashes: (Hash | Uint8Array | string)[]): Observable<DeriveCollectiveProposal[]> {
+  return (isFunction(api.query[section]?.proposals) && hashes.length
+    ? combineLatest([
+      of(hashes),
+      // this should simply be api.query[section].proposalOf.multi<Option<Proposal>>(hashes),
+      // however we have had cases on Edgeware where the indices have moved around after an
+      // upgrade, which results in invalid on-chain data
+      combineLatest(hashes.map((h) =>
+        api.query[section].proposalOf<Option<Proposal>>(h).pipe(
+          catchError(() => of(null))
+        )
+      )),
+      api.query[section].voting.multi<Option<Votes>>(hashes)
+    ])
+    : of<Result>([[], [], []])
+  ).pipe(
+    map((r) => parse(api, r))
  );
 }

-export function hasProposals (instanceId: string, api: ApiInterfaceRx, _section: Collective): () => Observable<boolean> {
-  const section = getInstance(api, _section);
-
-  return memo(instanceId, (): Observable<boolean> =>
-    of(isFunction(api.query[section]?.proposals))
+export function hasProposals (_section: Collective): (instanceId: string, api: ApiInterfaceRx) => () => Observable<boolean> {
+  return withSection(_section, (section, api) =>
+    (): Observable<boolean> =>
+      of(isFunction(api.query[section]?.proposals))
  );
 }

-export function proposalCount (instanceId: string, api: ApiInterfaceRx, _section: Collective): () => Observable<u32 | null> {
-  const section = getInstance(api, _section);
-
-  return memo(instanceId, (): Observable<u32 | null> =>
-    isFunction(api.query[section].proposalCount)
-      ? api.query[section as 'council'].proposalCount()
-      : of(null)
-  );
-}
-
-export function proposalHashes (instanceId: string, api: ApiInterfaceRx, _section: Collective): () => Observable<Hash[]> {
-  const section = getInstance(api, _section);
-
-  return memo(instanceId, (): Observable<Hash[]> =>
-    isFunction(api.query[section]?.proposals)
-      ? api.query[section as 'council'].proposals()
-      : of([])
-  );
-}
-
-export function proposals (instanceId: string, api: ApiInterfaceRx, _section: Collective): () => Observable<DeriveCollectiveProposal[]> {
-  const section = getInstance(api, _section);
-  const proposalsFrom = _proposalsFrom(instanceId, api, section);
-  const getHashes = proposalHashes(instanceId, api, _section);
-
-  return memo(instanceId, (): Observable<DeriveCollectiveProposal[]> =>
-    getHashes().pipe(
-      switchMap(proposalsFrom)
-    )
-  );
-}
-
-export function proposal (instanceId: string, api: ApiInterfaceRx, _section: Collective): (hash: Hash | Uint8Array | string) => Observable<DeriveCollectiveProposal | null> {
-  const section = getInstance(api, _section);
-  const proposalsFrom = _proposalsFrom(instanceId, api, section);
-
-  return memo(instanceId, (hash: Hash | Uint8Array | string): Observable<DeriveCollectiveProposal | null> =>
-    isFunction(api.query[section]?.proposals)
-      ? proposalsFrom([hash]).pipe(
-        map(([proposal]) => proposal)
+export function proposals (_section: Collective): (instanceId: string, api: ApiInterfaceRx) => () => Observable<DeriveCollectiveProposal[]> {
+  return withSection(_section, (section, api) =>
+    (): Observable<DeriveCollectiveProposal[]> =>
+      api.derive[section as 'council'].proposalHashes().pipe(
+        switchMap((all) => _proposalsFrom(section, api, all))
      )
-      : of(null)
  );
 }
+
+export function proposal (_section: Collective): (instanceId: string, api: ApiInterfaceRx) => (hash: Hash | Uint8Array | string) => Observable<DeriveCollectiveProposal | null> {
+  return withSection(_section, (section, api) =>
+    (hash: Hash | Uint8Array | string): Observable<DeriveCollectiveProposal | null> =>
+      isFunction(api.query[section]?.proposals)
+        ? firstObservable(_proposalsFrom(section, api, [hash]))
+        : of(null)
+  );
+}
+
+export const proposalCount = callMethod<u32 | null>('proposalCount', null);
+export const proposalHashes = callMethod<Hash[]>('proposals', []);
@@ -1,8 +1,17 @@
 // Copyright 2017-2021 @polkadot/api-derive authors & contributors
 // SPDX-License-Identifier: Apache-2.0

-export * from './members';
-export * from './prime';
-export * from './proposals';
+import { hasProposals as collectiveHasProposals, members as collectiveMembers, prime as collectivePrime, proposal as collectiveProposal, proposalCount as collectiveProposalCount, proposalHashes as collectiveProposalHashes, proposals as collectiveProposals } from '../collective';
+
 export * from './votes';
 export * from './votesOf';
+
+export const members = collectiveMembers('council');
+
+export const hasProposals = collectiveHasProposals('council');
+export const proposal = collectiveProposal('council');
+export const proposalCount = collectiveProposalCount('council');
+export const proposalHashes = collectiveProposalHashes('council');
+export const proposals = collectiveProposals('council');
+
+export const prime = collectivePrime('council');
@@ -1,13 +0,0 @@
-// Copyright 2017-2021 @polkadot/api-derive authors & contributors
-// SPDX-License-Identifier: Apache-2.0
-
-import type { Observable } from 'rxjs';
-import type { ApiInterfaceRx } from '@polkadot/api/types';
-import type { AccountId } from '@polkadot/types/interfaces';
-
-import { members as collectiveMembers } from '../collective';
-import { memo } from '../util';
-
-export function members (instanceId: string, api: ApiInterfaceRx): () => Observable<AccountId[]> {
-  return memo(instanceId, collectiveMembers(instanceId, api, 'council'));
-}
@@ -1,13 +0,0 @@
-// Copyright 2017-2021 @polkadot/api-derive authors & contributors
-// SPDX-License-Identifier: Apache-2.0
-
-import type { Observable } from 'rxjs';
-import type { ApiInterfaceRx } from '@polkadot/api/types';
-import type { AccountId } from '@polkadot/types/interfaces';
-
-import { prime as collectivePrime } from '../collective';
-import { memo } from '../util';
-
-export function prime (instanceId: string, api: ApiInterfaceRx): () => Observable<AccountId | null> {
-  return memo(instanceId, collectivePrime(instanceId, api, 'council'));
-}
@@ -1,31 +0,0 @@
-// Copyright 2017-2021 @polkadot/api-derive authors & contributors
-// SPDX-License-Identifier: Apache-2.0
-
-import type { Observable } from 'rxjs';
-import type { ApiInterfaceRx } from '@polkadot/api/types';
-import type { u32 } from '@polkadot/types';
-import type { Hash } from '@polkadot/types/interfaces';
-import type { DeriveCollectiveProposal } from '../types';
-
-import { hasProposals as collectiveHasProposals, proposal as collectiveProposal, proposalCount as collectiveProposalCount, proposalHashes as collectiveProposalHashes, proposals as collectiveProposals } from '../collective';
-import { memo } from '../util';
-
-export function hasProposals (instanceId: string, api: ApiInterfaceRx): () => Observable<boolean> {
-  return memo(instanceId, collectiveHasProposals(instanceId, api, 'council'));
-}
-
-export function proposal (instanceId: string, api: ApiInterfaceRx): (hash: Hash | Uint8Array | string) => Observable<DeriveCollectiveProposal | null> {
-  return memo(instanceId, collectiveProposal(instanceId, api, 'council'));
-}
-
-export function proposalCount (instanceId: string, api: ApiInterfaceRx): () => Observable<u32 | null> {
-  return memo(instanceId, collectiveProposalCount(instanceId, api, 'council'));
-}
-
-export function proposalHashes (instanceId: string, api: ApiInterfaceRx): () => Observable<Hash[]> {
-  return memo(instanceId, collectiveProposalHashes(instanceId, api, 'council'));
-}
-
-export function proposals (instanceId: string, api: ApiInterfaceRx): () => Observable<DeriveCollectiveProposal[]> {
-  return memo(instanceId, collectiveProposals(instanceId, api, 'council'));
-}
@@ -61,10 +61,8 @@ function schedulerEntries (api: ApiInterfaceRx): Observable<[BlockNumber[], (Opt
          // however we have had cases on Darwinia where the indices have moved around after an
          // upgrade, which results in invalid on-chain data
          combineLatest(blockNumbers.map((blockNumber) =>
-            api.query.scheduler.agenda(blockNumber).pipe(
-              // this does create an issue since it discards all at that block
-              catchError(() => of(null))
-            )
+            // this does create an issue since it discards all at that block
+            api.query.scheduler.agenda(blockNumber).pipe(catchError(() => of(null)))
          ))
        ])
        : of<[BlockNumber[], null[]]>([[], []]);
@@ -78,30 +76,23 @@ function queryScheduler (api: ApiInterfaceRx): Observable<DeriveDispatch[]> {
      const result: SchedulerInfo[] = [];

      blockNumbers.forEach((at, index): void => {
-        (agendas[index] || [])
-          .filter((opt) => opt.isSome)
-          .forEach((optScheduled): void => {
-            const scheduled = optScheduled.unwrap();
+        (agendas[index] || []).filter((o) => o.isSome).forEach((o): void => {
+          const scheduled = o.unwrap();

-            if (scheduled.maybeId.isSome) {
-              const id = scheduled.maybeId.unwrap().toHex();
+          if (scheduled.maybeId.isSome) {
+            const id = scheduled.maybeId.unwrap().toHex();

-              if (id.startsWith(DEMOCRACY_ID)) {
-                const [, index] = api.registry.createType('(u64, ReferendumIndex)', id);
-                const imageHash = scheduled.call.args[0] as Hash;
-
-                result.push({ at, imageHash, index });
-              }
-            }
-          });
+            id.startsWith(DEMOCRACY_ID) && result.push({ at, imageHash: scheduled.call.args[0] as Hash, index: api.registry.createType('(u64, ReferendumIndex)', id)[1] });
+          }
+        });
      });

-      return result.length
-        ? combineLatest([
-          of(result),
-          api.derive.democracy.preimages(result.map(({ imageHash }) => imageHash))
-        ])
-        : of([[], []]);
+      return combineLatest([
+        of(result),
+        result.length
+          ? api.derive.democracy.preimages(result.map(({ imageHash }) => imageHash))
+          : of([])
+      ]);
    }),
    map(([infos, images]): DeriveDispatch[] =>
      infos.map((info, index) => ({ ...info, image: images[index] }))
@@ -25,7 +25,11 @@ function parseEnd (api: ApiInterfaceRx, vote: Vote, { approved, end }: Referendu
  return [
    end,
    (approved.isTrue && vote.isAye) || (approved.isFalse && vote.isNay)
-      ? end.add(api.consts.democracy.enactmentPeriod.muln(LOCKUPS[vote.conviction.index]))
+      ? end.add(
+        (
+          api.consts.democracy.voteLockingPeriod ||
+          api.consts.democracy.enactmentPeriod
+        ).muln(LOCKUPS[vote.conviction.index]))
      : BN_ZERO
  ];
 }
@@ -50,7 +54,11 @@ function delegateLocks (api: ApiInterfaceRx, { balance, conviction, target }: Vo
        referendumId,
        unlockAt: unlockAt.isZero()
          ? unlockAt
-          : referendumEnd.add(api.consts.democracy.enactmentPeriod.muln(LOCKUPS[conviction.index])),
+          : referendumEnd.add(
+            (
+              api.consts.democracy.voteLockingPeriod ||
+              api.consts.democracy.enactmentPeriod
+            ).muln(LOCKUPS[conviction.index])),
        vote: api.registry.createType('Vote', { aye: vote.isAye, conviction })
      }))
    )
@@ -20,7 +20,6 @@ type Depositors = DepositorsNew | DepositorsOld;
 type Proposals = ITuple<[PropIndex, Hash, AccountId]>[];
 type Result = [Proposals, (DeriveProposalImage | undefined)[], Depositors[]];

-// eslint-disable-next-line @typescript-eslint/no-unused-vars
 function isNewDepositors (depositors: ITuple<[Vec<AccountId>, Balance]> | ITuple<[Balance, Vec<AccountId>]>): depositors is ITuple<[Vec<AccountId>, Balance]> {
  // Detect balance...
  // eslint-disable-next-line @typescript-eslint/unbound-method
@@ -6,6 +6,10 @@ import type { AccountId, Balance, BlockNumber, Hash, PropIndex, Proposal, Refere
 import type { PalletDemocracyReferendumStatus, PalletDemocracyVoteThreshold } from '@polkadot/types/lookup';
 import type { BN } from '@polkadot/util';

+export interface AtBlock {
+  at: BlockNumber;
+}
+
 export interface DeriveDemocracyLock {
  balance: Balance;
  isDelegated: boolean;
@@ -16,15 +20,13 @@ export interface DeriveDemocracyLock {
  vote: Vote;
 }

-export interface DeriveProposalImage {
-  at: BlockNumber;
+export interface DeriveProposalImage extends AtBlock {
  balance: Balance;
  proposal?: Proposal;
  proposer: AccountId;
 }

-export interface DeriveDispatch {
-  at: BlockNumber;
+export interface DeriveDispatch extends AtBlock {
  index: ReferendumIndex;
  imageHash: Hash;
  image?: DeriveProposalImage;
@@ -42,7 +42,20 @@ function sortAccounts ([, balanceA]: [AccountId, Balance], [, balanceB]: [Accoun
  return balanceB.cmp(balanceA);
 }

-function queryElections (api: ApiInterfaceRx): Observable<DeriveElectionsInfo> {
+function getConstants (api: ApiInterfaceRx, elections: string | null): Partial<DeriveElectionsInfo> {
+  return elections
+    ? {
+      candidacyBond: api.consts[elections].candidacyBond as Balance,
+      desiredRunnersUp: api.consts[elections].desiredRunnersUp as u32,
+      desiredSeats: api.consts[elections].desiredMembers as u32,
+      termDuration: api.consts[elections].termDuration as BlockNumber,
+      votingBond: api.consts[elections].votingBond as Balance
+    }
+    : {};
+}
+
+function getModules (api: ApiInterfaceRx): [string, string | null] {
+  const [council] = api.registry.getModuleInstances(api.runtimeVersion.specName.toString(), 'council') || ['council'];
  const elections = api.query.phragmenElection
    ? 'phragmenElection'
    : api.query.electionsPhragmen
@@ -50,43 +63,8 @@ function queryElections (api: ApiInterfaceRx): Observable<DeriveElectionsInfo> {
      : api.query.elections
        ? 'elections'
        : null;
-  const [council] = api.registry.getModuleInstances(api.runtimeVersion.specName.toString(), 'council') || ['council'];

-  return (
-    elections
-      ? api.queryMulti<[Vec<AccountId>, Vec<Candidate>, Vec<Member>, Vec<Member>]>([
-        api.query[council].members,
-        api.query[elections].candidates,
-        api.query[elections].members,
-        api.query[elections].runnersUp
-      ])
-      : combineLatest([
-        api.query[council].members<Vec<AccountId>>(),
-        of<Candidate[]>([]),
-        of<Member[]>([]),
-        of<Member[]>([])
-      ])
-  ).pipe(
-    map(([councilMembers, candidates, members, runnersUp]): DeriveElectionsInfo => ({
-      ...(
-        elections
-          ? {
-            candidacyBond: api.consts[elections].candidacyBond as Balance,
-            desiredRunnersUp: api.consts[elections].desiredRunnersUp as u32,
-            desiredSeats: api.consts[elections].desiredMembers as u32,
-            termDuration: api.consts[elections].termDuration as BlockNumber,
-            votingBond: api.consts[elections].votingBond as Balance
-          }
-          : {}
-      ),
-      candidateCount: api.registry.createType('u32', candidates.length),
-      candidates: candidates.map(getCandidate),
-      members: members.length
-        ? members.map(getAccountTuple).sort(sortAccounts)
-        : councilMembers.map((accountId): [AccountId, Balance] => [accountId, api.registry.createType('Balance')]),
-      runnersUp: runnersUp.map(getAccountTuple).sort(sortAccounts)
-    }))
-  );
+  return [council, elections];
 }

 /**
@@ -103,5 +81,33 @@ function queryElections (api: ApiInterfaceRx): Observable<DeriveElectionsInfo> {
 * ```
 */
 export function info (instanceId: string, api: ApiInterfaceRx): () => Observable<DeriveElectionsInfo> {
-  return memo(instanceId, (): Observable<DeriveElectionsInfo> => queryElections(api));
+  return memo(instanceId, (): Observable<DeriveElectionsInfo> => {
+    const [council, elections] = getModules(api);
+
+    return (
+      elections
+        ? api.queryMulti<[Vec<AccountId>, Vec<Candidate>, Vec<Member>, Vec<Member>]>([
+          api.query[council].members,
+          api.query[elections].candidates,
+          api.query[elections].members,
+          api.query[elections].runnersUp
+        ])
+        : combineLatest([
+          api.query[council].members<Vec<AccountId>>(),
+          of<Candidate[]>([]),
+          of<Member[]>([]),
+          of<Member[]>([])
+        ])
+    ).pipe(
+      map(([councilMembers, candidates, members, runnersUp]): DeriveElectionsInfo => ({
+        ...getConstants(api, elections),
+        candidateCount: api.registry.createType('u32', candidates.length),
+        candidates: candidates.map(getCandidate),
+        members: members.length
+          ? members.map(getAccountTuple).sort(sortAccounts)
+          : councilMembers.map((a): [AccountId, Balance] => [a, api.registry.createType('Balance')]),
+        runnersUp: runnersUp.map(getAccountTuple).sort(sortAccounts)
+      }))
+    );
+  });
 }
@@ -1,6 +1,14 @@
 // Copyright 2017-2021 @polkadot/api-derive authors & contributors
 // SPDX-License-Identifier: Apache-2.0

-export * from './members';
-export * from './prime';
-export * from './proposals';
+import { hasProposals as collectiveHasProposals, members as collectiveMembers, prime as collectivePrime, proposal as collectiveProposal, proposalCount as collectiveProposalCount, proposalHashes as collectiveProposalHashes, proposals as collectiveProposals } from '../collective';
+
+export const members = collectiveMembers('membership');
+
+export const hasProposals = collectiveHasProposals('membership');
+export const proposal = collectiveProposal('membership');
+export const proposalCount = collectiveProposalCount('membership');
+export const proposalHashes = collectiveProposalHashes('membership');
+export const proposals = collectiveProposals('membership');
+
+export const prime = collectivePrime('membership');
@@ -1,13 +0,0 @@
-// Copyright 2017-2021 @polkadot/api-derive authors & contributors
-// SPDX-License-Identifier: Apache-2.0
-
-import type { Observable } from 'rxjs';
-import type { ApiInterfaceRx } from '@polkadot/api/types';
-import type { AccountId } from '@polkadot/types/interfaces';
-
-import { members as collectiveMembers } from '../collective';
-import { memo } from '../util';
-
-export function members (instanceId: string, api: ApiInterfaceRx): () => Observable<AccountId[]> {
-  return memo(instanceId, collectiveMembers(instanceId, api, 'membership'));
-}
@@ -1,13 +0,0 @@
-// Copyright 2017-2021 @polkadot/api-derive authors & contributors
-// SPDX-License-Identifier: Apache-2.0
-
-import type { Observable } from 'rxjs';
-import type { ApiInterfaceRx } from '@polkadot/api/types';
-import type { AccountId } from '@polkadot/types/interfaces';
-
-import { prime as collectivePrime } from '../collective';
-import { memo } from '../util';
-
-export function prime (instanceId: string, api: ApiInterfaceRx): () => Observable<AccountId | null> {
-  return memo(instanceId, collectivePrime(instanceId, api, 'membership'));
-}
@@ -1,31 +0,0 @@
-// Copyright 2017-2021 @polkadot/api-derive authors & contributors
-// SPDX-License-Identifier: Apache-2.0
-
-import type { Observable } from 'rxjs';
-import type { ApiInterfaceRx } from '@polkadot/api/types';
-import type { u32 } from '@polkadot/types';
-import type { Hash } from '@polkadot/types/interfaces';
-import type { DeriveCollectiveProposal } from '../types';
-
-import { hasProposals as collectiveHasProposals, proposal as collectiveProposal, proposalCount as collectiveProposalCount, proposalHashes as collectiveProposalHashes, proposals as collectiveProposals } from '../collective';
-import { memo } from '../util';
-
-export function hasProposals (instanceId: string, api: ApiInterfaceRx): () => Observable<boolean> {
-  return memo(instanceId, collectiveHasProposals(instanceId, api, 'membership'));
-}
-
-export function proposal (instanceId: string, api: ApiInterfaceRx): (hash: Hash | Uint8Array | string) => Observable<DeriveCollectiveProposal | null> {
-  return memo(instanceId, collectiveProposal(instanceId, api, 'membership'));
-}
-
-export function proposalCount (instanceId: string, api: ApiInterfaceRx): () => Observable<u32 | null> {
-  return memo(instanceId, collectiveProposalCount(instanceId, api, 'membership'));
-}
-
-export function proposalHashes (instanceId: string, api: ApiInterfaceRx): () => Observable<Hash[]> {
-  return memo(instanceId, collectiveProposalHashes(instanceId, api, 'membership'));
-}
-
-export function proposals (instanceId: string, api: ApiInterfaceRx): () => Observable<DeriveCollectiveProposal[]> {
-  return memo(instanceId, collectiveProposals(instanceId, api, 'membership'));
-}
@@ -3,4 +3,4 @@

 // Auto-generated by @polkadot/dev, do not edit

-export const packageInfo = { name: '@polkadot/api-derive', version: '6.4.1' };
+export const packageInfo = { name: '@polkadot/api-derive', version: '6.12.1' };
@@ -1,17 +0,0 @@
-// Copyright 2017-2021 @polkadot/api-derive authors & contributors
-// SPDX-License-Identifier: Apache-2.0
-
-import type { Observable } from 'rxjs';
-import type { ApiInterfaceRx } from '@polkadot/api/types';
-import type { BlockNumber } from '@polkadot/types/interfaces';
-
-import { map } from 'rxjs';
-
-import { memo } from '../util';
-
-export function eraLength (instanceId: string, api: ApiInterfaceRx): () => Observable<BlockNumber> {
-  return memo(instanceId, (): Observable<BlockNumber> =>
-    api.derive.session.info().pipe(
-      map((info) => info.eraLength)
-    ));
-}
@@ -1,17 +0,0 @@
-// Copyright 2017-2021 @polkadot/api-derive authors & contributors
-// SPDX-License-Identifier: Apache-2.0
-
-import type { Observable } from 'rxjs';
-import type { ApiInterfaceRx } from '@polkadot/api/types';
-import type { BlockNumber } from '@polkadot/types/interfaces';
-
-import { map } from 'rxjs';
-
-import { memo } from '../util';
-
-export function eraProgress (instanceId: string, api: ApiInterfaceRx): () => Observable<BlockNumber> {
-  return memo(instanceId, (): Observable<BlockNumber> =>
-    api.derive.session.progress().pipe(
-      map((info) => info.eraProgress)
-    ));
-}
@@ -1,9 +1,6 @@
 // Copyright 2017-2021 @polkadot/api-derive authors & contributors
 // SPDX-License-Identifier: Apache-2.0

-export * from './eraLength';
-export * from './eraProgress';
 export * from './indexes';
 export * from './info';
 export * from './progress';
-export * from './sessionProgress';
@@ -4,7 +4,7 @@
 import type { Observable } from 'rxjs';
 import type { ApiInterfaceRx } from '@polkadot/api/types';
 import type { Option, u64 } from '@polkadot/types';
-import type { SessionIndex } from '@polkadot/types/interfaces';
+import type { BlockNumber, SessionIndex } from '@polkadot/types/interfaces';
 import type { DeriveSessionInfo, DeriveSessionProgress } from '../types';

 import { combineLatest, map, of, switchMap } from 'rxjs';
@@ -15,6 +15,15 @@ type ResultSlotsNoSession = [u64, u64, u64];
 type ResultSlots = [u64, u64, u64, Option<SessionIndex>];
 type ResultSlotsFlat = [u64, u64, u64, SessionIndex];

+function withProgressField (field: 'eraLength' | 'eraProgress' | 'sessionProgress'): (instanceId: string, api: ApiInterfaceRx) => () => Observable<BlockNumber> {
+  return (instanceId: string, api: ApiInterfaceRx) =>
+    memo(instanceId, (): Observable<BlockNumber> =>
+      api.derive.session.progress().pipe(
+        map((info) => info[field])
+      )
+    );
+}
+
 function createDerive (api: ApiInterfaceRx, info: DeriveSessionInfo, [currentSlot, epochIndex, epochOrGenesisStartSlot, activeEraStartSessionIndex]: ResultSlotsFlat): DeriveSessionProgress {
  const epochStartSlot = epochIndex.mul(info.sessionLength).iadd(epochOrGenesisStartSlot);
  const sessionProgress = currentSlot.sub(epochStartSlot);
@@ -77,3 +86,7 @@ export function progress (instanceId: string, api: ApiInterfaceRx): () => Observ
      : queryAura(api)
  );
 }
+
+export const eraLength = withProgressField('eraLength');
+export const eraProgress = withProgressField('eraProgress');
+export const sessionProgress = withProgressField('sessionProgress');
@@ -1,17 +0,0 @@
-// Copyright 2017-2021 @polkadot/api-derive authors & contributors
-// SPDX-License-Identifier: Apache-2.0
-
-import type { Observable } from 'rxjs';
-import type { ApiInterfaceRx } from '@polkadot/api/types';
-import type { BlockNumber } from '@polkadot/types/interfaces';
-
-import { map } from 'rxjs';
-
-import { memo } from '../util';
-
-export function sessionProgress (instanceId: string, api: ApiInterfaceRx): () => Observable<BlockNumber> {
-  return memo(instanceId, (): Observable<BlockNumber> =>
-    api.derive.session.progress().pipe(
-      map((info) => info.sessionProgress)
-    ));
-}
@@ -11,7 +11,7 @@ import { combineLatest, map, switchMap } from 'rxjs';

 import { BN, BN_ZERO } from '@polkadot/util';

-import { memo } from '../util';
+import { firstMemo, memo } from '../util';

 const QUERY_OPTS = {
  withDestination: true,
@@ -73,7 +73,9 @@ export function accounts (instanceId: string, api: ApiInterfaceRx): (accountIds:
          api.derive.staking.keysMulti(accountIds),
          api.derive.staking.queryMulti(accountIds, QUERY_OPTS)
        ]).pipe(
-          map(([keys, queries]) => queries.map((query, index) => parseResult(api, sessionInfo, keys[index], query)))
+          map(([keys, queries]) =>
+            queries.map((q, index) => parseResult(api, sessionInfo, keys[index], q))
+          )
        )
      )
    )
@@ -83,10 +85,7 @@ export function accounts (instanceId: string, api: ApiInterfaceRx): (accountIds:
 /**
 * @description From a stash, retrieve the controllerId and fill in all the relevant staking details
 */
-export function account (instanceId: string, api: ApiInterfaceRx): (accountId: Uint8Array | string) => Observable<DeriveStakingAccount> {
-  return memo(instanceId, (accountId: Uint8Array | string): Observable<DeriveStakingAccount> =>
-    api.derive.staking.accounts([accountId]).pipe(
-      map(([first]) => first)
-    )
-  );
-}
+export const account = firstMemo(
+  (api: ApiInterfaceRx, accountId: Uint8Array | string) =>
+    api.derive.staking.accounts([accountId])
+);
@@ -0,0 +1,46 @@
+// Copyright 2017-2021 @polkadot/api-derive authors & contributors
+// SPDX-License-Identifier: Apache-2.0
+
+import type { EraIndex } from '@polkadot/types/interfaces';
+
+import { deriveCache } from '../util';
+
+export function getEraCache <T> (CACHE_KEY: string, era: EraIndex, withActive?: boolean): [string, T | undefined] {
+  const cacheKey = `${CACHE_KEY}-${era.toString()}`;
+
+  return [
+    cacheKey,
+    withActive
+      ? undefined
+      : deriveCache.get<T>(cacheKey)
+  ];
+}
+
+export function getEraMultiCache <T> (CACHE_KEY: string, eras: EraIndex[], withActive?: boolean): T[] {
+  const cached: T[] = withActive
+    ? []
+    : eras
+      .map((e) => deriveCache.get<T>(`${CACHE_KEY}-${e.toString()}`))
+      .filter((v): v is T => !!v);
+
+  return cached;
+}
+
+export function setEraCache <T extends { era: EraIndex }> (cacheKey: string, withActive: boolean, value: T): T {
+  !withActive && deriveCache.set(cacheKey, value);
+
+  return value;
+}
+
+export function setEraMultiCache <T extends { era: EraIndex }> (CACHE_KEY: string, withActive: boolean, values: T[]): T[] {
+  !withActive && values.forEach((v) => deriveCache.set(`${CACHE_KEY}-${v.era.toString()}`, v));
+
+  return values;
+}
+
+export function filterCachedEras <T extends { era: EraIndex }> (eras: EraIndex[], cached: T[], query: T[]): T[] {
+  return eras.map((e) =>
+    cached.find(({ era }) => e.eq(era)) ||
+    query.find(({ era }) => e.eq(era)) as T
+  );
+}
@@ -8,9 +8,11 @@ import type { AccountId, EraIndex } from '@polkadot/types/interfaces';
 import type { PalletStakingExposure } from '@polkadot/types/lookup';
 import type { DeriveEraExposure, DeriveEraNominatorExposure, DeriveEraValidatorExposure } from '../types';

-import { combineLatest, map, of, switchMap } from 'rxjs';
+import { map, of } from 'rxjs';

-import { deriveCache, memo } from '../util';
+import { memo } from '../util';
+import { getEraCache, setEraCache } from './cache';
+import { combineEras, erasHistoricApply, singleEra } from './util';

 type KeysAndExposures = [StorageKey<[EraIndex, AccountId]>, PalletStakingExposure][];

@@ -36,45 +38,18 @@ function mapStakers (era: EraIndex, stakers: KeysAndExposures): DeriveEraExposur
  return { era, nominators, validators };
 }

-export function _eraExposure (instanceId: string, api: ApiInterfaceRx): (era: EraIndex, withActive: boolean) => Observable<DeriveEraExposure> {
-  return memo(instanceId, (era: EraIndex, withActive: boolean): Observable<DeriveEraExposure> => {
-    const cacheKey = `${CACHE_KEY}-${era.toString()}`;
-    const cached = withActive
-      ? undefined
-      : deriveCache.get<DeriveEraExposure>(cacheKey);
+export function _eraExposure (instanceId: string, api: ApiInterfaceRx): (era: EraIndex, withActive?: boolean) => Observable<DeriveEraExposure> {
+  return memo(instanceId, (era: EraIndex, withActive = false): Observable<DeriveEraExposure> => {
+    const [cacheKey, cached] = getEraCache<DeriveEraExposure>(CACHE_KEY, era, withActive);

    return cached
      ? of(cached)
      : api.query.staking.erasStakersClipped.entries(era).pipe(
-        map((stakers): DeriveEraExposure => {
-          const value = mapStakers(era, stakers);
-
-          !withActive && deriveCache.set(cacheKey, value);
-
-          return value;
-        })
+        map((r) => setEraCache(cacheKey, withActive, mapStakers(era, r)))
      );
  });
 }

-export function eraExposure (instanceId: string, api: ApiInterfaceRx): (era: EraIndex) => Observable<DeriveEraExposure> {
-  return memo(instanceId, (era: EraIndex): Observable<DeriveEraExposure> =>
-    api.derive.staking._eraExposure(era, true)
-  );
-}
-
-export function _erasExposure (instanceId: string, api: ApiInterfaceRx): (eras: EraIndex[], withActive: boolean) => Observable<DeriveEraExposure[]> {
-  return memo(instanceId, (eras: EraIndex[], withActive: boolean): Observable<DeriveEraExposure[]> =>
-    eras.length
-      ? combineLatest(eras.map((era) => api.derive.staking._eraExposure(era, withActive)))
-      : of([])
-  );
-}
-
-export function erasExposure (instanceId: string, api: ApiInterfaceRx): (withActive?: boolean) => Observable<DeriveEraExposure[]> {
-  return memo(instanceId, (withActive = false): Observable<DeriveEraExposure[]> =>
-    api.derive.staking.erasHistoric(withActive).pipe(
-      switchMap((eras) => api.derive.staking._erasExposure(eras, withActive))
-    )
-  );
-}
+export const eraExposure = singleEra('_eraExposure');
+export const _erasExposure = combineEras('_eraExposure');
+export const erasExposure = erasHistoricApply('_erasExposure');
@@ -13,8 +13,8 @@ import { BN_ONE, BN_ZERO } from '@polkadot/util';

 import { memo } from '../util';

-export function erasHistoric (instanceId: string, api: ApiInterfaceRx): (withActive: boolean) => Observable<EraIndex[]> {
-  return memo(instanceId, (withActive: boolean): Observable<EraIndex[]> =>
+export function erasHistoric (instanceId: string, api: ApiInterfaceRx): (withActive?: boolean) => Observable<EraIndex[]> {
+  return memo(instanceId, (withActive?: boolean): Observable<EraIndex[]> =>
    api.queryMulti<[Option<ActiveEraInfo>, u32]>([
      api.query.staking.activeEra,
      api.query.staking.historyDepth
@@ -7,12 +7,13 @@ import type { EraIndex } from '@polkadot/types/interfaces';
 import type { PalletStakingEraRewardPoints } from '@polkadot/types/lookup';
 import type { DeriveEraPoints, DeriveEraValPoints } from '../types';

-import { map, of, switchMap } from 'rxjs';
+import { map, of } from 'rxjs';

 import { BN_ZERO } from '@polkadot/util';

-import { deriveCache, memo } from '../util';
-import { filterEras } from './util';
+import { memo } from '../util';
+import { filterCachedEras, getEraMultiCache, setEraMultiCache } from './cache';
+import { erasHistoricApply, filterEras } from './util';

 const CACHE_KEY = 'eraPoints';

@@ -40,34 +41,15 @@ export function _erasPoints (instanceId: string, api: ApiInterfaceRx): (eras: Er
      return of([]);
    }

-    const cached: DeriveEraPoints[] = withActive
-      ? []
-      : eras
-        .map((era) => deriveCache.get<DeriveEraPoints>(`${CACHE_KEY}-${era.toString()}`))
-        .filter((value): value is DeriveEraPoints => !!value);
+    const cached = getEraMultiCache<DeriveEraPoints>(CACHE_KEY, eras, withActive);
    const remaining = filterEras(eras, cached);

    return !remaining.length
      ? of(cached)
      : api.query.staking.erasRewardPoints.multi(remaining).pipe(
-        map((points): DeriveEraPoints[] => {
-          const query = mapPoints(remaining, points);
-
-          !withActive && query.forEach((q) => deriveCache.set(`${CACHE_KEY}-${q.era.toString()}`, q));
-
-          return eras.map((era): DeriveEraPoints =>
-            cached.find((cached) => era.eq(cached.era)) ||
-            query.find((query) => era.eq(query.era)) as DeriveEraPoints
-          );
-        })
+        map((p) => filterCachedEras(eras, cached, setEraMultiCache(CACHE_KEY, withActive, mapPoints(remaining, p))))
      );
  });
 }

-export function erasPoints (instanceId: string, api: ApiInterfaceRx): (withActive?: boolean) => Observable<DeriveEraPoints[]> {
-  return memo(instanceId, (withActive = false): Observable<DeriveEraPoints[]> =>
-    api.derive.staking.erasHistoric(withActive).pipe(
-      switchMap((eras) => api.derive.staking._erasPoints(eras, withActive))
-    )
-  );
-}
+export const erasPoints = erasHistoricApply('_erasPoints');
@@ -8,9 +8,11 @@ import type { EraIndex } from '@polkadot/types/interfaces';
 import type { PalletStakingValidatorPrefs } from '@polkadot/types/lookup';
 import type { DeriveEraPrefs, DeriveEraValPrefs } from '../types';

-import { combineLatest, map, of, switchMap } from 'rxjs';
+import { map, of } from 'rxjs';

-import { deriveCache, memo } from '../util';
+import { memo } from '../util';
+import { getEraCache, setEraCache } from './cache';
+import { combineEras, erasHistoricApply, singleEra } from './util';

 const CACHE_KEY = 'eraPrefs';

@@ -26,43 +28,16 @@ function mapPrefs (era: EraIndex, all: [StorageKey, PalletStakingValidatorPrefs]

 export function _eraPrefs (instanceId: string, api: ApiInterfaceRx): (era: EraIndex, withActive: boolean) => Observable<DeriveEraPrefs> {
  return memo(instanceId, (era: EraIndex, withActive: boolean): Observable<DeriveEraPrefs> => {
-    const cacheKey = `${CACHE_KEY}-${era.toString()}`;
-    const cached = withActive
-      ? undefined
-      : deriveCache.get<DeriveEraPrefs>(cacheKey);
+    const [cacheKey, cached] = getEraCache<DeriveEraPrefs>(CACHE_KEY, era, withActive);

    return cached
      ? of(cached)
      : api.query.staking.erasValidatorPrefs.entries(era).pipe(
-        map((prefs): DeriveEraPrefs => {
-          const value = mapPrefs(era, prefs);
-
-          !withActive && deriveCache.set(cacheKey, value);
-
-          return value;
-        })
+        map((r) => setEraCache(cacheKey, withActive, mapPrefs(era, r)))
      );
  });
 }

-export function eraPrefs (instanceId: string, api: ApiInterfaceRx): (era: EraIndex) => Observable<DeriveEraPrefs> {
-  return memo(instanceId, (era: EraIndex): Observable<DeriveEraPrefs> =>
-    api.derive.staking._eraPrefs(era, true)
-  );
-}
-
-export function _erasPrefs (instanceId: string, api: ApiInterfaceRx): (eras: EraIndex[], withActive: boolean) => Observable<DeriveEraPrefs[]> {
-  return memo(instanceId, (eras: EraIndex[], withActive: boolean): Observable<DeriveEraPrefs[]> =>
-    eras.length
-      ? combineLatest(eras.map((era) => api.derive.staking._eraPrefs(era, withActive)))
-      : of([])
-  );
-}
-
-export function erasPrefs (instanceId: string, api: ApiInterfaceRx): (withActive?: boolean) => Observable<DeriveEraPrefs[]> {
-  return memo(instanceId, (withActive = false): Observable<DeriveEraPrefs[]> =>
-    api.derive.staking.erasHistoric(withActive).pipe(
-      switchMap((eras) => api.derive.staking._erasPrefs(eras, withActive))
-    )
-  );
-}
+export const eraPrefs = singleEra('_eraPrefs');
+export const _erasPrefs = combineEras('_eraPrefs');
+export const erasPrefs = erasHistoricApply('_erasPrefs');
@@ -7,10 +7,11 @@ import type { Option } from '@polkadot/types';
 import type { Balance, EraIndex } from '@polkadot/types/interfaces';
 import type { DeriveEraRewards } from '../types';

-import { map, of, switchMap } from 'rxjs';
+import { map, of } from 'rxjs';

-import { deriveCache, memo } from '../util';
-import { filterEras } from './util';
+import { memo } from '../util';
+import { filterCachedEras, getEraMultiCache, setEraMultiCache } from './cache';
+import { erasHistoricApply, filterEras } from './util';

 const CACHE_KEY = 'eraRewards';

@@ -27,11 +28,7 @@ export function _erasRewards (instanceId: string, api: ApiInterfaceRx): (eras: E
      return of([]);
    }

-    const cached: DeriveEraRewards[] = withActive
-      ? []
-      : eras
-        .map((era) => deriveCache.get<DeriveEraRewards>(`${CACHE_KEY}-${era.toString()}`))
-        .filter((value): value is DeriveEraRewards => !!value);
+    const cached = getEraMultiCache<DeriveEraRewards>(CACHE_KEY, eras, withActive);
    const remaining = filterEras(eras, cached);

    if (!remaining.length) {
@@ -39,24 +36,9 @@ export function _erasRewards (instanceId: string, api: ApiInterfaceRx): (eras: E
    }

    return api.query.staking.erasValidatorReward.multi(remaining).pipe(
-      map((optRewards) => {
-        const query = mapRewards(remaining, optRewards);
-
-        !withActive && query.forEach((q) => deriveCache.set(`${CACHE_KEY}-${q.era.toString()}`, q));
-
-        return eras.map((era): DeriveEraRewards =>
-          cached.find((cached) => era.eq(cached.era)) ||
-          query.find((query) => era.eq(query.era)) as DeriveEraRewards
-        );
-      })
+      map((r) => filterCachedEras(eras, cached, setEraMultiCache(CACHE_KEY, withActive, mapRewards(remaining, r))))
    );
  });
 }

-export function erasRewards (instanceId: string, api: ApiInterfaceRx): (withActive?: boolean) => Observable<DeriveEraRewards[]> {
-  return memo(instanceId, (withActive = false): Observable<DeriveEraRewards[]> =>
-    api.derive.staking.erasHistoric(withActive).pipe(
-      switchMap((eras) => api.derive.staking._erasRewards(eras, withActive))
-    )
-  );
-}
+export const erasRewards = erasHistoricApply('_erasRewards');
@@ -8,9 +8,11 @@ import type { BalanceOf, EraIndex, Perbill } from '@polkadot/types/interfaces';
 import type { ITuple } from '@polkadot/types/types';
 import type { DeriveEraSlashes, DeriveEraValSlash } from '../types';

-import { combineLatest, map, of, switchMap } from 'rxjs';
+import { combineLatest, map, of } from 'rxjs';

-import { deriveCache, memo } from '../util';
+import { memo } from '../util';
+import { getEraCache, setEraCache } from './cache';
+import { combineEras, erasHistoricApply, singleEra } from './util';

 const CACHE_KEY = 'eraSlashes';

@@ -31,10 +33,7 @@ function mapSlashes (era: EraIndex, noms: [StorageKey, Option<BalanceOf>][], val

 export function _eraSlashes (instanceId: string, api: ApiInterfaceRx): (era: EraIndex, withActive: boolean) => Observable<DeriveEraSlashes> {
  return memo(instanceId, (era: EraIndex, withActive: boolean): Observable<DeriveEraSlashes> => {
-    const cacheKey = `${CACHE_KEY}-${era.toString()}`;
-    const cached = withActive
-      ? undefined
-      : deriveCache.get<DeriveEraSlashes>(cacheKey);
+    const [cacheKey, cached] = getEraCache<DeriveEraSlashes>(CACHE_KEY, era, withActive);

    return cached
      ? of(cached)
@@ -42,37 +41,11 @@ export function _eraSlashes (instanceId: string, api: ApiInterfaceRx): (era: Era
        api.query.staking.nominatorSlashInEra.entries(era),
        api.query.staking.validatorSlashInEra.entries(era)
      ]).pipe(
-        map(([noms, vals]): DeriveEraSlashes => {
-          const value = mapSlashes(era, noms, vals);
-
-          !withActive && deriveCache.set(cacheKey, value);
-
-          return value;
-        })
+        map(([n, v]) => setEraCache(cacheKey, withActive, mapSlashes(era, n, v)))
      );
  });
 }

-export function eraSlashes (instanceId: string, api: ApiInterfaceRx): (era: EraIndex) => Observable<DeriveEraSlashes> {
-  return memo(instanceId, (era: EraIndex): Observable<DeriveEraSlashes> =>
-    api.derive.staking._eraSlashes(era, true)
-  );
-}
-
-export function _erasSlashes (instanceId: string, api: ApiInterfaceRx): (eras: EraIndex[], withActive: boolean) => Observable<DeriveEraSlashes[]> {
-  return memo(instanceId, (eras: EraIndex[], withActive: boolean): Observable<DeriveEraSlashes[]> =>
-    eras.length
-      ? combineLatest(
-        eras.map((era) => api.derive.staking._eraSlashes(era, withActive))
-      )
-      : of([])
-  );
-}
-
-export function erasSlashes (instanceId: string, api: ApiInterfaceRx): (withActive?: boolean) => Observable<DeriveEraSlashes[]> {
-  return memo(instanceId, (withActive = false): Observable<DeriveEraSlashes[]> =>
-    api.derive.staking.erasHistoric(withActive).pipe(
-      switchMap((eras) => api.derive.staking._erasSlashes(eras, withActive))
-    )
-  );
-}
+export const eraSlashes = singleEra('_eraSlashes');
+export const _erasSlashes = combineEras('_eraSlashes');
+export const erasSlashes = erasHistoricApply('_erasSlashes');
@@ -11,7 +11,7 @@ import type { DeriveStakingKeys } from './types';

 import { combineLatest, map, of, switchMap } from 'rxjs';

-import { memo } from '../util';
+import { firstMemo, memo } from '../util';

 function extractsIds (stashId: Uint8Array | string, queuedKeys: [AccountId, NodeRuntimeSessionKeys | AccountId[]][], nextKeys: Option<NodeRuntimeSessionKeys>): DeriveStakingKeys {
  const sessionIds = (queuedKeys.find(([currentId]) => currentId.eq(stashId)) || [undefined, [] as AccountId[]])[1];
@@ -27,13 +27,10 @@ function extractsIds (stashId: Uint8Array | string, queuedKeys: [AccountId, Node
  };
 }

-export function keys (instanceId: string, api: ApiInterfaceRx): (stashId: Uint8Array | string) => Observable<DeriveStakingKeys> {
-  return memo(instanceId, (stashId: Uint8Array | string): Observable<DeriveStakingKeys> =>
-    api.derive.staking.keysMulti([stashId]).pipe(
-      map(([first]) => first)
-    )
-  );
-}
+export const keys = firstMemo(
+  (api: ApiInterfaceRx, stashId: Uint8Array | string) =>
+    api.derive.staking.keysMulti([stashId])
+);

 export function keysMulti (instanceId: string, api: ApiInterfaceRx): (stashIds: (Uint8Array | string)[]) => Observable<DeriveStakingKeys[]> {
  return memo(instanceId, (stashIds: (Uint8Array | string)[]): Observable<DeriveStakingKeys[]> =>
@@ -7,17 +7,18 @@ import type { EraIndex } from '@polkadot/types/interfaces';
 import type { PalletStakingExposure } from '@polkadot/types/lookup';
 import type { DeriveOwnExposure } from '../types';

-import { map, of, switchMap } from 'rxjs';
+import { map, of } from 'rxjs';

-import { memo } from '../util';
+import { firstMemo, memo } from '../util';
+import { erasHistoricApplyAccount } from './util';

 export function _ownExposures (instanceId: string, api: ApiInterfaceRx): (accountId: Uint8Array | string, eras: EraIndex[], withActive: boolean) => Observable<DeriveOwnExposure[]> {
  // eslint-disable-next-line @typescript-eslint/no-unused-vars
  return memo(instanceId, (accountId: Uint8Array | string, eras: EraIndex[], _withActive: boolean): Observable<DeriveOwnExposure[]> =>
    eras.length
      ? api.queryMulti<PalletStakingExposure[]>([
-        ...eras.map((era): QueryableStorageMultiArg<'rxjs'> => [api.query.staking.erasStakersClipped, [era, accountId]]),
-        ...eras.map((era): QueryableStorageMultiArg<'rxjs'> => [api.query.staking.erasStakers, [era, accountId]])
+        ...eras.map((e): QueryableStorageMultiArg<'rxjs'> => [api.query.staking.erasStakersClipped, [e, accountId]]),
+        ...eras.map((e): QueryableStorageMultiArg<'rxjs'> => [api.query.staking.erasStakers, [e, accountId]])
      ]).pipe(
        map((all): DeriveOwnExposure[] =>
          eras.map((era, index) => ({ clipped: all[index], era, exposure: all[eras.length + index] }))
@@ -27,20 +28,9 @@ export function _ownExposures (instanceId: string, api: ApiInterfaceRx): (accoun
  );
 }

-export function ownExposure (instanceId: string, api: ApiInterfaceRx): (accountId: Uint8Array | string, era: EraIndex) => Observable<DeriveOwnExposure> {
-  return memo(instanceId, (accountId: Uint8Array | string, era: EraIndex): Observable<DeriveOwnExposure> =>
-    api.derive.staking._ownExposures(accountId, [era], true).pipe(
-      map(([first]) => first)
-    )
-  );
-}
+export const ownExposure = firstMemo(
+  (api: ApiInterfaceRx, accountId: Uint8Array | string, era: EraIndex) =>
+    api.derive.staking._ownExposures(accountId, [era], true)
+);

-export function ownExposures (instanceId: string, api: ApiInterfaceRx): (accountId: Uint8Array | string, withActive?: boolean) => Observable<DeriveOwnExposure[]> {
-  return memo(instanceId, (accountId: Uint8Array | string, withActive = false): Observable<DeriveOwnExposure[]> => {
-    return api.derive.staking.erasHistoric(withActive).pipe(
-      switchMap((eras) =>
-        api.derive.staking._ownExposures(accountId, eras, withActive)
-      )
-    );
-  });
-}
+export const ownExposures = erasHistoricApplyAccount('_ownExposures');
@@ -8,17 +8,18 @@ import type { BalanceOf, EraIndex, Perbill } from '@polkadot/types/interfaces';
 import type { ITuple } from '@polkadot/types/types';
 import type { DeriveStakerSlashes } from '../types';

-import { map, of, switchMap } from 'rxjs';
+import { map, of } from 'rxjs';

-import { memo } from '../util';
+import { firstMemo, memo } from '../util';
+import { erasHistoricApplyAccount } from './util';

 export function _ownSlashes (instanceId: string, api: ApiInterfaceRx): (accountId: Uint8Array | string, eras: EraIndex[], withActive: boolean) => Observable<DeriveStakerSlashes[]> {
  // eslint-disable-next-line @typescript-eslint/no-unused-vars
  return memo(instanceId, (accountId: Uint8Array | string, eras: EraIndex[], _withActive: boolean): Observable<DeriveStakerSlashes[]> =>
    eras.length
      ? api.queryMulti<(Option<ITuple<[Perbill, BalanceOf]>> | Option<BalanceOf>)[]>([
-        ...eras.map((era): QueryableStorageMultiArg<'rxjs'> => [api.query.staking.validatorSlashInEra, [era, accountId]]),
-        ...eras.map((era): QueryableStorageMultiArg<'rxjs'> => [api.query.staking.nominatorSlashInEra, [era, accountId]])
+        ...eras.map((e): QueryableStorageMultiArg<'rxjs'> => [api.query.staking.validatorSlashInEra, [e, accountId]]),
+        ...eras.map((e): QueryableStorageMultiArg<'rxjs'> => [api.query.staking.nominatorSlashInEra, [e, accountId]])
      ]).pipe(
        map((values): DeriveStakerSlashes[] =>
          eras.map((era, index) => ({
@@ -33,20 +34,9 @@ export function _ownSlashes (instanceId: string, api: ApiInterfaceRx): (accountI
  );
 }

-export function ownSlash (instanceId: string, api: ApiInterfaceRx): (accountId: Uint8Array | string, era: EraIndex) => Observable<DeriveStakerSlashes> {
-  return memo(instanceId, (accountId: Uint8Array | string, era: EraIndex): Observable<DeriveStakerSlashes> =>
-    api.derive.staking._ownSlashes(accountId, [era], true).pipe(
-      map(([first]) => first)
-    )
-  );
-}
+export const ownSlash = firstMemo(
+  (api: ApiInterfaceRx, accountId: Uint8Array | string, era: EraIndex) =>
+    api.derive.staking._ownSlashes(accountId, [era], true)
+);

-export function ownSlashes (instanceId: string, api: ApiInterfaceRx): (accountId: Uint8Array | string, withActive?: boolean) => Observable<DeriveStakerSlashes[]> {
-  return memo(instanceId, (accountId: Uint8Array | string, withActive = false): Observable<DeriveStakerSlashes[]> => {
-    return api.derive.staking.erasHistoric(withActive).pipe(
-      switchMap((eras) =>
-        api.derive.staking._ownSlashes(accountId, eras, withActive)
-      )
-    );
-  });
-}
+export const ownSlashes = erasHistoricApplyAccount('_ownSlashes');
@@ -10,7 +10,7 @@ import type { DeriveStakingQuery, StakingQueryFlags } from '../types';

 import { combineLatest, map, of, switchMap } from 'rxjs';

-import { memo } from '../util';
+import { firstMemo, memo } from '../util';

 function parseDetails (stashId: AccountId, controllerIdOpt: Option<AccountId> | null, nominatorsOpt: Option<PalletStakingNominations>, rewardDestination: PalletStakingRewardDestination, validatorPrefs: PalletStakingValidatorPrefs, exposure: PalletStakingExposure, stakingLedgerOpt: Option<PalletStakingStakingLedger>): DeriveStakingQuery {
  return {
@@ -29,8 +29,8 @@ function parseDetails (stashId: AccountId, controllerIdOpt: Option<AccountId> |

 function getLedgers (api: ApiInterfaceRx, optIds: (Option<AccountId> | null)[], { withLedger = false }: StakingQueryFlags): Observable<Option<PalletStakingStakingLedger>[]> {
  const ids = optIds
-    .filter((opt): opt is Option<AccountId> => withLedger && !!opt && opt.isSome)
-    .map((opt) => opt.unwrap());
+    .filter((o): o is Option<AccountId> => withLedger && !!o && o.isSome)
+    .map((o) => o.unwrap());
  const emptyLed = api.registry.createType<Option<PalletStakingStakingLedger>>('Option<StakingLedger>');

  return (
@@ -93,13 +93,10 @@ function getBatch (api: ApiInterfaceRx, activeEra: EraIndex, stashIds: AccountId
 /**
 * @description From a stash, retrieve the controllerId and all relevant details
 */
-export function query (instanceId: string, api: ApiInterfaceRx): (accountId: Uint8Array | string, flags: StakingQueryFlags) => Observable<DeriveStakingQuery> {
-  return memo(instanceId, (accountId: Uint8Array | string, flags: StakingQueryFlags): Observable<DeriveStakingQuery> =>
-    api.derive.staking.queryMulti([accountId], flags).pipe(
-      map(([first]) => first)
-    )
-  );
-}
+export const query = firstMemo(
+  (api: ApiInterfaceRx, accountId: Uint8Array | string, flags: StakingQueryFlags) =>
+    api.derive.staking.queryMulti([accountId], flags)
+);

 export function queryMulti (instanceId: string, api: ApiInterfaceRx): (accountIds: (Uint8Array | string)[], flags: StakingQueryFlags) => Observable<DeriveStakingQuery[]> {
  return memo(instanceId, (accountIds: (Uint8Array | string)[], flags: StakingQueryFlags): Observable<DeriveStakingQuery[]> =>
@@ -8,10 +8,10 @@ import type { DeriveEraValidatorExposure, DeriveStakerExposure } from '../types'

 import { map, switchMap } from 'rxjs';

-import { memo } from '../util';
+import { firstMemo, memo } from '../util';

-export function _stakerExposures (instanceId: string, api: ApiInterfaceRx): (accountIds: (Uint8Array | string)[], eras: EraIndex[], withActive: boolean) => Observable<DeriveStakerExposure[][]> {
-  return memo(instanceId, (accountIds: (Uint8Array | string)[], eras: EraIndex[], withActive: boolean): Observable<DeriveStakerExposure[][]> => {
+export function _stakerExposures (instanceId: string, api: ApiInterfaceRx): (accountIds: (Uint8Array | string)[], eras: EraIndex[], withActive?: boolean) => Observable<DeriveStakerExposure[][]> {
+  return memo(instanceId, (accountIds: (Uint8Array | string)[], eras: EraIndex[], withActive = false): Observable<DeriveStakerExposure[][]> => {
    const stakerIds = accountIds.map((a) => api.registry.createType('AccountId', a).toString());

    return api.derive.staking._erasExposure(eras, withActive).pipe(
@@ -46,10 +46,7 @@ export function stakerExposures (instanceId: string, api: ApiInterfaceRx): (acco
  );
 }

-export function stakerExposure (instanceId: string, api: ApiInterfaceRx): (accountId: Uint8Array | string, withActive?: boolean) => Observable<DeriveStakerExposure[]> {
-  return memo(instanceId, (accountId: Uint8Array | string, withActive = false): Observable<DeriveStakerExposure[]> =>
-    api.derive.staking.stakerExposures([accountId], withActive).pipe(
-      map(([first]) => first)
-    )
-  );
-}
+export const stakerExposure = firstMemo(
+  (api: ApiInterfaceRx, accountId: Uint8Array | string, withActive?: boolean) =>
+    api.derive.staking.stakerExposures([accountId], withActive)
+);
@@ -6,9 +6,10 @@ import type { ApiInterfaceRx } from '@polkadot/api/types';
 import type { EraIndex } from '@polkadot/types/interfaces';
 import type { DeriveStakerPoints } from '../types';

-import { map, switchMap } from 'rxjs';
+import { map } from 'rxjs';

 import { memo } from '../util';
+import { erasHistoricApplyAccount } from './util';

 export function _stakerPoints (instanceId: string, api: ApiInterfaceRx): (accountId: Uint8Array | string, eras: EraIndex[], withActive: boolean) => Observable<DeriveStakerPoints[]> {
  return memo(instanceId, (accountId: Uint8Array | string, eras: EraIndex[], withActive: boolean): Observable<DeriveStakerPoints[]> => {
@@ -26,10 +27,4 @@ export function _stakerPoints (instanceId: string, api: ApiInterfaceRx): (accoun
  });
 }

-export function stakerPoints (instanceId: string, api: ApiInterfaceRx): (accountId: Uint8Array | string, withActive?: boolean) => Observable<DeriveStakerPoints[]> {
-  return memo(instanceId, (accountId: Uint8Array | string, withActive = false): Observable<DeriveStakerPoints[]> =>
-    api.derive.staking.erasHistoric(withActive).pipe(
-      switchMap((eras) => api.derive.staking._stakerPoints(accountId, eras, withActive))
-    )
-  );
-}
+export const stakerPoints = erasHistoricApplyAccount('_stakerPoints');
@@ -6,14 +6,15 @@ import type { ApiInterfaceRx } from '@polkadot/api/types';
 import type { EraIndex } from '@polkadot/types/interfaces';
 import type { DeriveStakerPrefs } from '../types';

-import { map, switchMap } from 'rxjs';
+import { map } from 'rxjs';

 import { memo } from '../util';
+import { erasHistoricApplyAccount } from './util';

 export function _stakerPrefs (instanceId: string, api: ApiInterfaceRx): (accountId: Uint8Array | string, eras: EraIndex[], withActive: boolean) => Observable<DeriveStakerPrefs[]> {
  // eslint-disable-next-line @typescript-eslint/no-unused-vars
  return memo(instanceId, (accountId: Uint8Array | string, eras: EraIndex[], _withActive: boolean): Observable<DeriveStakerPrefs[]> =>
-    api.query.staking.erasValidatorPrefs.multi(eras.map((era) => [era, accountId])).pipe(
+    api.query.staking.erasValidatorPrefs.multi(eras.map((e) => [e, accountId])).pipe(
      map((all): DeriveStakerPrefs[] =>
        all.map((validatorPrefs, index): DeriveStakerPrefs => ({
          era: eras[index],
@@ -24,10 +25,4 @@ export function _stakerPrefs (instanceId: string, api: ApiInterfaceRx): (account
  );
 }

-export function stakerPrefs (instanceId: string, api: ApiInterfaceRx): (accountId: Uint8Array | string, withActive?: boolean) => Observable<DeriveStakerPrefs[]> {
-  return memo(instanceId, (accountId: Uint8Array | string, withActive = false): Observable<DeriveStakerPrefs[]> =>
-    api.derive.staking.erasHistoric(withActive).pipe(
-      switchMap((eras) => api.derive.staking._stakerPrefs(accountId, eras, withActive))
-    )
-  );
-}
+export const stakerPrefs = erasHistoricApplyAccount('_stakerPrefs');
@@ -13,7 +13,7 @@ import { combineLatest, map, of, switchMap } from 'rxjs';

 import { BN_BILLION, BN_ZERO } from '@polkadot/util';

-import { memo } from '../util';
+import { firstMemo, memo } from '../util';

 type ErasResult = [DeriveEraPoints[], DeriveEraPrefs[], DeriveEraRewards[]];

@@ -98,7 +98,7 @@ function removeClaimed (validators: string[], queryValidators: DeriveStakingQuer
    if (index !== -1) {
      const valLedger = queryValidators[index].stakingLedger;

-      if (valLedger?.claimedRewards.some((era) => reward.era.eq(era))) {
+      if (valLedger?.claimedRewards.some((e) => reward.era.eq(e))) {
        rm.push(validatorId);
      }
    }
@@ -110,14 +110,14 @@ function removeClaimed (validators: string[], queryValidators: DeriveStakingQuer
 }

 function filterRewards (eras: EraIndex[], valInfo: [string, DeriveStakingQuery][], { rewards, stakingLedger }: { rewards: DeriveStakerReward[]; stakingLedger: PalletStakingStakingLedger }): DeriveStakerReward[] {
-  const filter = eras.filter((era) => !stakingLedger.claimedRewards.some((e) => e.eq(era)));
+  const filter = eras.filter((e) => !stakingLedger.claimedRewards.some((s) => s.eq(e)));
  const validators = valInfo.map(([v]) => v);
  const queryValidators = valInfo.map(([, q]) => q);

  return rewards
    .filter(({ isEmpty }) => !isEmpty)
    .filter((reward): boolean => {
-      if (!filter.some((filter) => reward.era.eq(filter))) {
+      if (!filter.some((e) => reward.era.eq(e))) {
        return false;
      }

@@ -132,8 +132,8 @@ function filterRewards (eras: EraIndex[], valInfo: [string, DeriveStakingQuery][
    }));
 }

-export function _stakerRewardsEras (instanceId: string, api: ApiInterfaceRx): (eras: EraIndex[], withActive: boolean) => Observable<ErasResult> {
-  return memo(instanceId, (eras: EraIndex[], withActive: boolean): Observable<ErasResult> =>
+export function _stakerRewardsEras (instanceId: string, api: ApiInterfaceRx): (eras: EraIndex[], withActive?: boolean) => Observable<ErasResult> {
+  return memo(instanceId, (eras: EraIndex[], withActive = false): Observable<ErasResult> =>
    combineLatest([
      api.derive.staking._erasPoints(eras, withActive),
      api.derive.staking._erasPrefs(eras, withActive),
@@ -142,8 +142,8 @@ export function _stakerRewardsEras (instanceId: string, api: ApiInterfaceRx): (e
  );
 }

-export function _stakerRewards (instanceId: string, api: ApiInterfaceRx): (accountIds: (Uint8Array | string)[], eras: EraIndex[], withActive: boolean) => Observable<DeriveStakerReward[][]> {
-  return memo(instanceId, (accountIds: (Uint8Array | string)[], eras: EraIndex[], withActive: boolean): Observable<DeriveStakerReward[][]> =>
+export function _stakerRewards (instanceId: string, api: ApiInterfaceRx): (accountIds: (Uint8Array | string)[], eras: EraIndex[], withActive?: boolean) => Observable<DeriveStakerReward[][]> {
+  return memo(instanceId, (accountIds: (Uint8Array | string)[], eras: EraIndex[], withActive = false): Observable<DeriveStakerReward[][]> =>
    combineLatest([
      api.derive.staking.queryMulti(accountIds, { withLedger: true }),
      api.derive.staking._stakerExposures(accountIds, eras, withActive),
@@ -184,14 +184,12 @@ export function _stakerRewards (instanceId: string, api: ApiInterfaceRx): (accou
  );
 }

-export function stakerRewards (instanceId: string, api: ApiInterfaceRx): (accountId: Uint8Array | string, withActive?: boolean) => Observable<DeriveStakerReward[]> {
-  return memo(instanceId, (accountId: Uint8Array | string, withActive = false): Observable<DeriveStakerReward[]> =>
+export const stakerRewards = firstMemo(
+  (api: ApiInterfaceRx, accountId: Uint8Array | string, withActive?: boolean) =>
    api.derive.staking.erasHistoric(withActive).pipe(
-      switchMap((eras) => api.derive.staking._stakerRewards([accountId], eras, withActive)),
-      map(([first]) => first)
+      switchMap((eras) => api.derive.staking._stakerRewards([accountId], eras, withActive))
    )
-  );
-}
+);

 export function stakerRewardsMultiEras (instanceId: string, api: ApiInterfaceRx): (accountIds: (Uint8Array | string)[], eras: EraIndex[]) => Observable<DeriveStakerReward[][]> {
  return memo(instanceId, (accountIds: (Uint8Array | string)[], eras: EraIndex[]): Observable<DeriveStakerReward[][]> =>
@@ -6,9 +6,10 @@ import type { ApiInterfaceRx } from '@polkadot/api/types';
 import type { EraIndex } from '@polkadot/types/interfaces';
 import type { DeriveStakerSlashes } from '../types';

-import { map, switchMap } from 'rxjs';
+import { map } from 'rxjs';

 import { memo } from '../util';
+import { erasHistoricApplyAccount } from './util';

 export function _stakerSlashes (instanceId: string, api: ApiInterfaceRx): (accountId: Uint8Array | string, eras: EraIndex[], withActive: boolean) => Observable<DeriveStakerSlashes[]> {
  return memo(instanceId, (accountId: Uint8Array | string, eras: EraIndex[], withActive: boolean): Observable<DeriveStakerSlashes[]> => {
@@ -25,10 +26,4 @@ export function _stakerSlashes (instanceId: string, api: ApiInterfaceRx): (accou
  });
 }

-export function stakerSlashes (instanceId: string, api: ApiInterfaceRx): (accountId: Uint8Array | string, withActive?: boolean) => Observable<DeriveStakerSlashes[]> {
-  return memo(instanceId, (accountId: Uint8Array | string, withActive = false): Observable<DeriveStakerSlashes[]> =>
-    api.derive.staking.erasHistoric(withActive).pipe(
-      switchMap((eras) => api.derive.staking._stakerSlashes(accountId, eras, withActive))
-    )
-  );
-}
+export const stakerSlashes = erasHistoricApplyAccount('_stakerSlashes');
@@ -1,8 +1,60 @@
 // Copyright 2017-2021 @polkadot/api-derive authors & contributors
 // SPDX-License-Identifier: Apache-2.0

+import type { Observable } from 'rxjs';
+import type { ApiInterfaceRx, ObsInnerType } from '@polkadot/api/types';
 import type { EraIndex } from '@polkadot/types/interfaces';
+import type { ExactDerive } from '../bundle';
+
+import { combineLatest, of, switchMap } from 'rxjs';
+
+import { memo } from '../util';
+
+type ApplyReturn<T extends keyof ExactDerive['staking']> = ReturnType<ExactDerive['staking'][T]>;

 export function filterEras <T extends { era: EraIndex }> (eras: EraIndex[], list: T[]): EraIndex[] {
-  return eras.filter((era) => !list.some((entry) => era.eq(entry.era)));
+  return eras.filter((e) => !list.some(({ era }) => e.eq(era)));
+}
+
+export function erasHistoricApply <F extends '_erasExposure' | '_erasPoints' | '_erasPrefs' | '_erasRewards' | '_erasSlashes'> (fn: F): (instanceId: string, api: ApiInterfaceRx) => (withActive?: boolean) => ApplyReturn<F> {
+  return (instanceId: string, api: ApiInterfaceRx) =>
+    // Cannot quite get the typing right, but it is right in the code
+    // eslint-disable-next-line @typescript-eslint/no-unsafe-return
+    memo(instanceId, (withActive = false) =>
+      api.derive.staking.erasHistoric(withActive).pipe(
+        switchMap((e) => api.derive.staking[fn](e, withActive))
+      )
+    ) as any;
+}
+
+export function erasHistoricApplyAccount <F extends '_ownExposures' | '_ownSlashes' | '_stakerPoints' | '_stakerPrefs' | '_stakerSlashes'> (fn: F): (instanceId: string, api: ApiInterfaceRx) => (accountId: string | Uint8Array, withActive?: boolean) => ApplyReturn<F> {
+  return (instanceId: string, api: ApiInterfaceRx) =>
+    // Cannot quite get the typing right, but it is right in the code
+    // eslint-disable-next-line @typescript-eslint/no-unsafe-return
+    memo(instanceId, (accountId: string | Uint8Array, withActive = false) =>
+      api.derive.staking.erasHistoric(withActive).pipe(
+        switchMap((e) => api.derive.staking[fn](accountId, e, withActive))
+      )
+    ) as any;
+}
+
+export function singleEra <F extends '_eraExposure' | '_eraPrefs' | '_eraSlashes'> (fn: F): (instanceId: string, api: ApiInterfaceRx) => (era: EraIndex) => ApplyReturn<F> {
+  return (instanceId: string, api: ApiInterfaceRx) =>
+    // Cannot quite get the typing right, but it is right in the code
+    // eslint-disable-next-line @typescript-eslint/no-unsafe-return
+    memo(instanceId, (era: EraIndex) =>
+      api.derive.staking[fn](era, true)
+    ) as any;
+}
+
+export function combineEras <F extends '_eraExposure' | '_eraPrefs' | '_eraSlashes'> (fn: F): (instanceId: string, api: ApiInterfaceRx) => (eras: EraIndex[], withActive: boolean) => Observable<ObsInnerType<ApplyReturn<F>>[]> {
+  return (instanceId: string, api: ApiInterfaceRx) =>
+    // Cannot quite get the typing right, but it is right in the code
+    // eslint-disable-next-line @typescript-eslint/no-unsafe-return
+    memo(instanceId, (eras: EraIndex[], withActive: boolean) =>
+      // eslint-disable-next-line @typescript-eslint/no-unsafe-return
+      eras.length
+        ? combineLatest(eras.map((e) => api.derive.staking[fn](e, withActive)))
+        : of([])
+    ) as any;
 }
@@ -1,6 +1,14 @@
 // Copyright 2017-2021 @polkadot/api-derive authors & contributors
 // SPDX-License-Identifier: Apache-2.0

-export * from './members';
-export * from './prime';
-export * from './proposals';
+import { hasProposals as collectiveHasProposals, members as collectiveMembers, prime as collectivePrime, proposal as collectiveProposal, proposalCount as collectiveProposalCount, proposalHashes as collectiveProposalHashes, proposals as collectiveProposals } from '../collective';
+
+export const members = collectiveMembers('technicalCommittee');
+
+export const hasProposals = collectiveHasProposals('technicalCommittee');
+export const proposal = collectiveProposal('technicalCommittee');
+export const proposalCount = collectiveProposalCount('technicalCommittee');
+export const proposalHashes = collectiveProposalHashes('technicalCommittee');
+export const proposals = collectiveProposals('technicalCommittee');
+
+export const prime = collectivePrime('technicalCommittee');
@@ -1,13 +0,0 @@
-// Copyright 2017-2021 @polkadot/api-derive authors & contributors
-// SPDX-License-Identifier: Apache-2.0
-
-import type { Observable } from 'rxjs';
-import type { ApiInterfaceRx } from '@polkadot/api/types';
-import type { AccountId } from '@polkadot/types/interfaces';
-
-import { members as collectiveMembers } from '../collective';
-import { memo } from '../util';
-
-export function members (instanceId: string, api: ApiInterfaceRx): () => Observable<AccountId[]> {
-  return memo(instanceId, collectiveMembers(instanceId, api, 'technicalCommittee'));
-}
@@ -1,13 +0,0 @@
-// Copyright 2017-2021 @polkadot/api-derive authors & contributors
-// SPDX-License-Identifier: Apache-2.0
-
-import type { Observable } from 'rxjs';
-import type { ApiInterfaceRx } from '@polkadot/api/types';
-import type { AccountId } from '@polkadot/types/interfaces';
-
-import { prime as collectivePrime } from '../collective';
-import { memo } from '../util';
-
-export function prime (instanceId: string, api: ApiInterfaceRx): () => Observable<AccountId | null> {
-  return memo(instanceId, collectivePrime(instanceId, api, 'technicalCommittee'));
-}
--- a/Show More
+++ b/Show More