Sub/unsub cleanups (#1535)

* Sub/unsub cleanups

* drr full idAndIndex

* Memo on nick call

* refCountDelay

* Remove scheduler param, always asap

* Flatten

* Test cleanups

* Make tests pass

* Remove logs

* Drop nick memo

* sourceConnection.unsubscribe

* Small cleanups

packages/api-derive/src/accounts/idAndIndex.ts

@@ -5,17 +5,47 @@
 import { AccountId, AccountIndex, Address } from '@polkadot/types/interfaces';
 
 import { Observable, of } from 'rxjs';
-import { map, startWith } from 'rxjs/operators';
+import { map } from 'rxjs/operators';
 import { ApiInterfaceRx } from '@polkadot/api/types';
 import { isU8a } from '@polkadot/util';
 import { decodeAddress } from '@polkadot/util-crypto';
 import { createType } from '@polkadot/types';
 import { idToIndex } from './idToIndex';
 import { indexToId } from './indexToId';
-import { drr } from '../util/drr';
+import { drr } from '../util';
+
+interface Calls {
+  idToIndexCall (accountId: string | AccountId): Observable<AccountIndex | undefined>;
+  indexToIdCall (accountIndex: string | AccountIndex): Observable<AccountId | undefined>;
+}
 
 export type AccountIdAndIndex = [AccountId?, AccountIndex?];
 
+function retrieve (address: Address | AccountId | AccountIndex | string | null | undefined, { idToIndexCall, indexToIdCall }: Calls): 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 === 32) {
+      const accountId = createType('AccountId', decoded);
+
+      return idToIndexCall(accountId).pipe(
+        map((accountIndex): AccountIdAndIndex => [accountId, accountIndex] as AccountIdAndIndex)
+      );
+    }
+
+    const accountIndex = createType('AccountIndex', decoded);
+
+    return indexToIdCall(accountIndex).pipe(
+      map((accountId): AccountIdAndIndex => [accountId, accountIndex] as AccountIdAndIndex)
+    );
+  } catch (error) {
+    return of([undefined, undefined] as AccountIdAndIndex);
+  }
+}
+
 /**
  * @name idAndIndex
  * @param {(Address | AccountId | AccountIndex | string | null)} address - An accounts address in various formats.
@@ -30,35 +60,11 @@ export type AccountIdAndIndex = [AccountId?, AccountIndex?];
  * ```
  */
 export function idAndIndex (api: ApiInterfaceRx): (address?: Address | AccountId | AccountIndex | string | null) => Observable<AccountIdAndIndex> {
-  const idToIndexCall = idToIndex(api);
-  const indexToIdCall = indexToId(api);
-
-  return (address?: Address | AccountId | AccountIndex | 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 === 32) {
-        const accountId = createType('AccountId', decoded);
-
-        return idToIndexCall(accountId).pipe(
-          startWith(undefined),
-          map((accountIndex): AccountIdAndIndex => [accountId, accountIndex] as AccountIdAndIndex),
-          drr()
-        );
-      }
-
-      const accountIndex = createType('AccountIndex', decoded);
-
-      return indexToIdCall(accountIndex).pipe(
-        startWith(undefined),
-        map((accountId): AccountIdAndIndex => [accountId, accountIndex] as AccountIdAndIndex),
-        drr()
-      );
-    } catch (error) {
-      return of([undefined, undefined] as AccountIdAndIndex).pipe(drr());
-    }
+  const calls = {
+    idToIndexCall: idToIndex(api),
+    indexToIdCall: indexToId(api)
   };
+
+  return (address?: Address | AccountId | AccountIndex | string | null): Observable<AccountIdAndIndex> =>
+    retrieve(address, calls).pipe(drr());
 }

packages/api-derive/src/accounts/idToIndex.ts

@@ -9,7 +9,7 @@ import { map, startWith } from 'rxjs/operators';
 import { ApiInterfaceRx } from '@polkadot/api/types';
 
 import { indexes, AccountIndexes } from './indexes';
-import { drr } from '../util/drr';
+import { drr } from '../util';
 
 /**
  * @name idToIndex

packages/api-derive/src/accounts/indexToId.ts

@@ -10,7 +10,7 @@ import { ApiInterfaceRx } from '@polkadot/api/types';
 import { ENUMSET_SIZE } from '@polkadot/types/primitive/Generic/AccountIndex';
 import { createType, ClassOf, Vec } from '@polkadot/types';
 
-import { drr } from '../util/drr';
+import { drr } from '../util';
 
 /**
  * @name indexToId

packages/api-derive/src/accounts/indexes.ts

@@ -10,7 +10,7 @@ import { map, switchMap } from 'rxjs/operators';
 import { ENUMSET_SIZE } from '@polkadot/types/primitive/Generic/AccountIndex';
 import { createType } from '@polkadot/types';
 
-import { drr } from '../util/drr';
+import { drr } from '../util';
 
 export type AccountIndexes = Record<string, AccountIndex>;
 

packages/api-derive/src/accounts/info.ts

@@ -7,39 +7,44 @@ import { AccountId, AccountIndex, Address, Balance } from '@polkadot/types/inter
 import { Codec } from '@polkadot/types/types';
 import { DeriveAccountInfo } from '../types';
 
-import { Observable, of } from 'rxjs';
+import { Observable, of, combineLatest } from 'rxjs';
 import { map, switchMap } from 'rxjs/operators';
 import { Bytes, Option, u32 } from '@polkadot/types';
 import { u8aToString } from '@polkadot/util';
 
-import { drr } from '../util/drr';
+import { drr } from '../util';
 import { idAndIndex } from './idAndIndex';
 
+function retrieveNick (api: ApiInterfaceRx): (accountId?: AccountId) => Observable<Option<[Bytes, Balance] & Codec> | undefined> {
+  return (accountId?: AccountId): Observable<Option<[Bytes, Balance] & Codec> | undefined> =>
+    accountId && api.query.nicks
+      ? api.query.nicks.nameOf<Option<[Bytes, Balance] & Codec>>(accountId)
+      : of(undefined);
+}
+
 /**
  * @name info
  * @description Returns aux. info with regards to an account, current that includes the accountId, accountIndex and nickname
  */
 export function info (api: ApiInterfaceRx): (address?: AccountIndex | AccountId | Address | string | null) => Observable<DeriveAccountInfo> {
   const idAndIndexCall = idAndIndex(api);
+  const nickCall = retrieveNick(api);
 
-  // TODO We would really like to pass in an Address or AccountIndex here as well
   return (address?: AccountIndex | AccountId | Address | string | null): Observable<DeriveAccountInfo> =>
     idAndIndexCall(address).pipe(
-      switchMap(([accountId, accountIndex]): Observable<DeriveAccountInfo> =>
-        accountId && api.query.nicks
-          ? api.query.nicks
-            .nameOf<Option<[Bytes, Balance] & Codec>>(accountId)
-            .pipe(
-              map((result): DeriveAccountInfo => ({
-                accountId,
-                accountIndex,
-                nickname: result.isSome
-                  ? u8aToString(result.unwrap()[0]).substr(0, (api.consts.nicks.maxLength as u32).toNumber())
-                  : undefined
-              }))
-            )
-          : of({ accountId, accountIndex })
-      ),
+      switchMap(([accountId, accountIndex]): Observable<[DeriveAccountInfo, Option<[Bytes, Balance] & Codec>?]> => {
+        return combineLatest([
+          of({ accountId, accountIndex }),
+          nickCall(accountId)
+        ]);
+      }),
+      map(([{ accountId, accountIndex }, nameOf]): DeriveAccountInfo => ({
+        accountId,
+        accountIndex,
+        nickname: nameOf && nameOf.isSome
+          ? u8aToString(nameOf.unwrap()[0]).substr(0, (api.consts.nicks.maxLength as u32).toNumber())
+          : undefined
+      })),
       drr()
     );
 }

packages/api-derive/src/balances/all.ts

@@ -14,7 +14,7 @@ import { bnMax } from '@polkadot/util';
 import { info } from '../accounts/info';
 import { bestNumber } from '../chain/bestNumber';
 import { DerivedBalances } from '../types';
-import { drr } from '../util/drr';
+import { drr } from '../util';
 
 type ResultBalance = [Balance, Balance, BalanceLock[], Option<VestingSchedule>];
 type Result = [AccountId, BlockNumber, ResultBalance, Index];

packages/api-derive/src/balances/fees.ts

@@ -9,7 +9,7 @@ import { DerivedFees } from '../types';
 import { Observable, of } from 'rxjs';
 import { map } from 'rxjs/operators';
 
-import { drr } from '../util/drr';
+import { drr } from '../util';
 
 type Result = [Balance, Balance, Balance, Balance, Balance];
 

packages/api-derive/src/balances/votingBalances.ts

@@ -8,7 +8,7 @@ import { combineLatest, Observable, of } from 'rxjs';
 import { ApiInterfaceRx } from '@polkadot/api/types';
 
 import { DerivedBalances } from '../types';
-import { drr } from '../util/drr';
+import { drr } from '../util';
 import { all } from './all';
 
 export function votingBalances (api: ApiInterfaceRx): (addresses?: (AccountId | AccountIndex | Address | string)[]) => Observable<DerivedBalances[]> {

packages/api-derive/src/balances/votingBalancesNominatorsFor.ts

@@ -11,7 +11,7 @@ import { Vec } from '@polkadot/types';
 
 import { info } from '../accounts/info';
 import { DerivedBalances } from '../types';
-import { drr } from '../util/drr';
+import { drr } from '../util';
 import { votingBalances } from './votingBalances';
 
 export function votingBalancesNominatorsFor (api: ApiInterfaceRx): (address: AccountId | AccountIndex | Address | string) => Observable<DerivedBalances[]> {

packages/api-derive/src/chain/bestNumber.ts

@@ -8,7 +8,7 @@ import { Observable } from 'rxjs';
 import { map } from 'rxjs/operators';
 import { ApiInterfaceRx } from '@polkadot/api/types';
 
-import { drr } from '../util/drr';
+import { drr } from '../util';
 
 /**
  * @name bestNumber

packages/api-derive/src/chain/bestNumberFinalized.ts

@@ -8,7 +8,7 @@ import { Observable } from 'rxjs';
 import { map } from 'rxjs/operators';
 import { ApiInterfaceRx } from '@polkadot/api/types';
 
-import { drr } from '../util/drr';
+import { drr } from '../util';
 
 /**
  * @name bestNumberFinalized

packages/api-derive/src/chain/bestNumberLag.ts

@@ -9,7 +9,7 @@ import { map } from 'rxjs/operators';
 import { ApiInterfaceRx } from '@polkadot/api/types';
 import { createType } from '@polkadot/types';
 
-import { drr } from '../util/drr';
+import { drr } from '../util';
 import { bestNumber } from './bestNumber';
 import { bestNumberFinalized } from './bestNumberFinalized';
 

packages/api-derive/src/chain/getHeader.ts

@@ -7,7 +7,7 @@ import { catchError, map } from 'rxjs/operators';
 import { ApiInterfaceRx } from '@polkadot/api/types';
 
 import { HeaderExtended } from '../type';
-import { drr } from '../util/drr';
+import { drr } from '../util';
 import { HeaderAndValidators } from './subscribeNewHeads';
 
 /**

packages/api-derive/src/chain/subscribeNewHeads.ts

@@ -9,7 +9,7 @@ import { Observable, combineLatest, of } from 'rxjs';
 import { map, switchMap } from 'rxjs/operators';
 
 import { HeaderExtended } from '../type';
-import { drr } from '../util/drr';
+import { drr } from '../util';
 
 export type HeaderAndValidators = [Header, AccountId[]];
 

packages/api-derive/src/contracts/fees.ts

@@ -9,7 +9,7 @@ import BN from 'bn.js';
 import { Observable, of } from 'rxjs';
 import { map } from 'rxjs/operators';
 
-import { drr } from '../util/drr';
+import { drr } from '../util';
 
 type ResultV2 = [BN, BN, BN, BN, BN, BN, BN, BN, BN, BN];
 

packages/api-derive/src/democracy/referendumInfo.ts

@@ -12,7 +12,7 @@ import { Option } from '@polkadot/types';
 import { isNull } from '@polkadot/util';
 
 import { ReferendumInfoExtended } from '../type';
-import { drr } from '../util/drr';
+import { drr } from '../util';
 
 export function constructInfo (index: BN | number, optionInfo?: Option<ReferendumInfo>): Option<ReferendumInfoExtended> {
   const info = optionInfo

packages/api-derive/src/democracy/referendumInfos.ts

@@ -11,7 +11,7 @@ import { ApiInterfaceRx } from '@polkadot/api/types';
 import { Option, Vec } from '@polkadot/types';
 
 import { ReferendumInfoExtended } from '../type';
-import { drr } from '../util/drr';
+import { drr } from '../util';
 import { constructInfo } from './referendumInfo';
 
 export function referendumInfos (api: ApiInterfaceRx): (ids?: (BN | number)[]) => Observable<Option<ReferendumInfoExtended>[]> {

packages/api-derive/src/democracy/referendumVotesFor.ts

@@ -11,7 +11,7 @@ import { ApiInterfaceRx } from '@polkadot/api/types';
 import { Vec, createType } from '@polkadot/types';
 
 import { DerivedBalances, DerivedReferendumVote } from '../types';
-import { drr } from '../util/drr';
+import { drr } from '../util';
 import { votes } from './votes';
 import { votingBalances } from '../balances/votingBalances';
 

packages/api-derive/src/democracy/referendums.ts

@@ -11,7 +11,7 @@ import { ApiInterfaceRx } from '@polkadot/api/types';
 import { Option } from '@polkadot/types';
 
 import { ReferendumInfoExtended } from '../type';
-import { drr } from '../util/drr';
+import { drr } from '../util';
 import { referendumInfos } from './referendumInfos';
 
 export function referendums (api: ApiInterfaceRx): () => Observable<Option<ReferendumInfoExtended>[]> {

packages/api-derive/src/democracy/votes.ts

@@ -9,7 +9,7 @@ import { Observable, of } from 'rxjs';
 import { ApiInterfaceRx } from '@polkadot/api/types';
 import { Vec } from '@polkadot/types';
 
-import { drr } from '../util/drr';
+import { drr } from '../util';
 
 export function votes (api: ApiInterfaceRx): (referendumId: BN, accountIds?: AccountId[]) => Observable<Vote[]> {
   return (referendumId: BN, accountIds: AccountId[] = []): Observable<Vote[]> => {

packages/api-derive/src/elections/approvalsOf.ts

@@ -9,7 +9,7 @@ import { Observable } from 'rxjs';
 import { Vec } from '@polkadot/types';
 import { switchMap, map } from 'rxjs/operators';
 import { approvalFlagsToBools } from '../util/approvalFlagsToBools';
-import { drr } from '../util/drr';
+import { drr } from '../util';
 
 /**
  * @name approvalsOf

packages/api-derive/src/elections/approvalsOfAt.ts

@@ -11,7 +11,7 @@ import { ApiInterfaceRx } from '@polkadot/api/types';
 import { Vec } from '@polkadot/types';
 
 import { approvalFlagsToBools } from '../util/approvalFlagsToBools';
-import { drr } from '../util/drr';
+import { drr } from '../util';
 
 /**
  * @name approvalsOfAt

packages/api-derive/src/elections/info.ts

@@ -11,7 +11,7 @@ import { ApiInterfaceRx } from '@polkadot/api/types';
 import { createType, Vec, u32 } from '@polkadot/types';
 
 import { DerivedElectionsInfo } from '../types';
-import { drr } from '../util/drr';
+import { drr } from '../util';
 
 type ResultElectionsInner = [u32, u32, Vec<[AccountId, BlockNumber] & Codec>, SetIndex, BlockNumber, VoteIndex, SetIndex];
 type ResultElections = [Vec<AccountId>, ResultElectionsInner];

packages/api-derive/src/elections/voterPositions.ts

@@ -10,7 +10,7 @@ import { DerivedVoterPositions } from '../types';
 import BN from 'bn.js';
 import { of, combineLatest, Observable } from 'rxjs';
 import { switchMap, map } from 'rxjs/operators';
-import { drr } from '../util/drr';
+import { drr } from '../util';
 
 /**
  * @name voterPositions

packages/api-derive/src/elections/voters.ts

@@ -10,7 +10,7 @@ import { Observable } from 'rxjs';
 import { map } from 'rxjs/operators';
 import { createType, Vec } from '@polkadot/types';
 
-import { drr } from '../util/drr';
+import { drr } from '../util';
 import { voterPositions } from './voterPositions';
 
 /**

packages/api-derive/src/imOnline/receivedHeartbeats.ts

@@ -10,7 +10,7 @@ import { map, switchMap } from 'rxjs/operators';
 import { ApiInterfaceRx } from '@polkadot/api/types';
 import { Bytes, Vec, u32 } from '@polkadot/types';
 
-import { drr } from '../util/drr';
+import { drr } from '../util';
 
 /**
  * @description Return a boolean array indicating whether the passed accounts had received heartbeats in the current session

packages/api-derive/src/session/eraLength.ts

@@ -8,7 +8,7 @@ import { Observable } from 'rxjs';
 import { map } from 'rxjs/operators';
 import { ApiInterfaceRx } from '@polkadot/api/types';
 
-import { drr } from '../util/drr';
+import { drr } from '../util';
 import { info } from './info';
 
 export function eraLength (api: ApiInterfaceRx): () => Observable<BlockNumber> {

packages/api-derive/src/session/eraProgress.ts

@@ -7,7 +7,7 @@ import { Observable } from 'rxjs';
 import { map } from 'rxjs/operators';
 import { ApiInterfaceRx } from '@polkadot/api/types';
 
-import { drr } from '../util/drr';
+import { drr } from '../util';
 import { info } from './info';
 
 export function eraProgress (api: ApiInterfaceRx): () => Observable<BN> {

packages/api-derive/src/session/info.ts

@@ -10,7 +10,7 @@ import { map } from 'rxjs/operators';
 import { ApiInterfaceRx } from '@polkadot/api/types';
 import { Option, u64, createType } from '@polkadot/types';
 
-import { drr } from '../util/drr';
+import { drr } from '../util';
 import { bestNumber } from '../chain';
 
 type ResultV1Session = [SessionIndex, Option<BlockNumber>, BlockNumber, BlockNumber, SessionIndex];

packages/api-derive/src/session/sessionProgress.ts

@@ -8,7 +8,7 @@ import { Observable } from 'rxjs';
 import { map } from 'rxjs/operators';
 import { ApiInterfaceRx } from '@polkadot/api/types';
 
-import { drr } from '../util/drr';
+import { drr } from '../util';
 import { info } from './info';
 
 export function sessionProgress (api: ApiInterfaceRx): () => Observable<BlockNumber> {

packages/api-derive/src/staking/all.ts

@@ -8,7 +8,7 @@ import { Observable, combineLatest } from 'rxjs';
 import { switchMap } from 'rxjs/operators';
 import { ApiInterfaceRx } from '@polkadot/api/types';
 
-import { drr } from '../util/drr';
+import { drr } from '../util';
 import { controllers } from './controllers';
 import { info } from './info';
 

packages/api-derive/src/staking/controllers.ts

@@ -10,7 +10,7 @@ import { switchMap } from 'rxjs/operators';
 import { ApiInterfaceRx } from '@polkadot/api/types';
 import { Option } from '@polkadot/types';
 
-import { drr } from '../util/drr';
+import { drr } from '../util';
 
 /**
  * @description From the list of stash accounts, retrieve the list of controllers

packages/api-derive/src/staking/info.ts

@@ -20,7 +20,7 @@ import { isUndefined } from '@polkadot/util';
 import { bestNumber } from '../chain/bestNumber';
 import { eraLength } from '../session/eraLength';
 import { recentlyOffline } from './recentlyOffline';
-import { drr } from '../util/drr';
+import { drr } from '../util';
 
 interface Calls {
   bestNumberCall (): Observable<BlockNumber>;

packages/api-derive/src/staking/recentlyOffline.ts

@@ -11,7 +11,7 @@ import { map } from 'rxjs/operators';
 import { ApiInterfaceRx } from '@polkadot/api/types';
 import { DerivedRecentlyOffline } from '../types';
 
-import { drr } from '../util/drr';
+import { drr } from '../util';
 
 type OfflineResult = [AccountId, BlockNumber, BN][] & Codec;
 

packages/api-derive/src/util/index.ts

@@ -2,4 +2,6 @@
 // This software may be modified and distributed under the terms
 // of the Apache-2.0 license. See the LICENSE file for details.
 
+export { drr } from '@polkadot/rpc-core/rxjs';
+
 export * from './approvalFlagsToBools';

packages/rpc-core/src/cached.spec.ts

@@ -44,22 +44,41 @@ describe('Cached Observables', (): void => {
     expect(observable2).not.toBe(observable1);
   });
 
-  it('clears cache if there are no more subscribers', (): void => {
+  it('subscribes to the same one if within the period (unbsub delay)', (done): void => {
+    const observable1 = rpc.chain.subscribeNewHeads();
+    const sub1 = observable1.subscribe();
+
+    sub1.unsubscribe();
+
+    setTimeout((): void => {
+      const observable2 = rpc.chain.subscribeNewHeads();
+      const sub2 = observable2.subscribe();
+
+      expect(observable1).toBe(observable2);
+
+      sub2.unsubscribe();
+      done();
+    }, 500);
+  });
+
+  it('clears cache if there are no more subscribers', (done): void => {
     const observable1 = rpc.chain.subscribeNewHeads();
     const observable2 = rpc.chain.subscribeNewHeads();
-
-    expect(observable1).toBe(observable2);
-
     const sub1 = observable1.subscribe();
     const sub2 = observable2.subscribe();
 
+    expect(observable1).toBe(observable2);
+
     sub1.unsubscribe();
     sub2.unsubscribe();
 
-    // No more subscribers, now create a new observable
-    const observable3 = rpc.chain.subscribeNewHeads();
+    setTimeout((): void => {
+      // No more subscribers, now create a new observable
+      const observable3 = rpc.chain.subscribeNewHeads();
 
-    expect(observable3).not.toBe(observable1);
+      expect(observable3).not.toBe(observable1);
+      done();
+    }, 3500);
   });
 
   it('creates different observables for different methods but same arguments', (): void => {

packages/rpc-core/src/index.ts

@@ -10,7 +10,7 @@ import { RpcInterfaceMethod, UserRpc } from './types';
 
 import memoizee from 'memoizee';
 import { combineLatest, from, Observable, Observer, of, throwError } from 'rxjs';
-import { catchError, distinctUntilChanged, map, publishReplay, refCount, switchMap } from 'rxjs/operators';
+import { catchError, map, publishReplay, refCount, switchMap } from 'rxjs/operators';
 import jsonrpc from '@polkadot/jsonrpc';
 import jsonrpcMethod from '@polkadot/jsonrpc/create/method';
 import jsonrpcParam from '@polkadot/jsonrpc/create/param';
@@ -18,6 +18,8 @@ import { Option, StorageKey, Vec, createClass } from '@polkadot/types';
 import { createTypeUnsafe } from '@polkadot/types/codec';
 import { assert, isFunction, isNull, isNumber, logger, u8aToU8a } from '@polkadot/util';
 
+import { drr } from './rxjs';
+
 type UserRpcConverted = Record<string, Record<string, RpcMethod>>;
 
 const l = logger('rpc-core');
@@ -223,6 +225,19 @@ export default class Rpc implements RpcInterface {
     return call as RpcInterfaceMethod;
   }
 
+  // create a subscriptor, it subscribes once and resolves with the id as subscribe
+  private createSubscriber ({ subType, subName, paramsJson, update }: { subType: string; subName: string; paramsJson: AnyJson[]; update: (error?: Error, result?: any) => void }, errorHandler: (error: Error) => void): Promise<number> {
+    return new Promise((resolve, reject): void => {
+      this.provider
+        .subscribe(subType, subName, paramsJson, update)
+        .then(resolve)
+        .catch((error): void => {
+          errorHandler(error);
+          reject(error);
+        });
+    });
+  }
+
   private createMethodSubscribe (method: RpcMethod): RpcInterfaceMethod {
     const [updateType, subMethod, unsubMethod] = method.pubsub;
     const subName = `${method.section}_${subMethod}`;
@@ -253,9 +268,7 @@ export default class Rpc implements RpcInterface {
             observer.next(this.formatOutput(method, params, result));
           };
 
-          subscriptionPromise = this.provider
-            .subscribe(subType, subName, paramsJson, update)
-            .catch(errorHandler);
+          subscriptionPromise = this.createSubscriber({ subType, subName, paramsJson, update }, errorHandler);
         } catch (error) {
           errorHandler(error);
         }
@@ -281,18 +294,9 @@ export default class Rpc implements RpcInterface {
                 ? this.provider.unsubscribe(subType, unsubName, subscriptionId)
                 : Promise.resolve(false)
             )
-            .catch((error: Error): void =>
-              l.error(this.createErrorMessage(method, error))
-            );
+            .catch((error: Error): void => l.error(this.createErrorMessage(method, error)));
         };
-      }).pipe(
-        // Duplicated in api-derive/util/drr
-        distinctUntilChanged((a: any, b: any): boolean =>
-          JSON.stringify({ value: a }) === JSON.stringify({ value: b })
-        ),
-        publishReplay(1),
-        refCount()
-      );
+      }).pipe(drr());
     };
 
     const memoized = memoizee(call, {

packages/rpc-core/src/replay.spec.ts

@@ -57,12 +57,12 @@ describe('replay', (): void => {
     const subscription = rpc.chain.subscribeNewHeads().subscribe((): void => {
       subscription.unsubscribe();
 
-      // There's a promise inside .unsubscribe(), wait a bit
+      // There's a promise inside .unsubscribe(), wait a bit (> 2s)
       setTimeout((): void => {
         // eslint-disable-next-line @typescript-eslint/unbound-method
         expect(rpc.provider.unsubscribe).toHaveBeenCalled();
         done();
-      }, 200);
+      }, 3500);
     });
   });
 });

packages/rpc-core/src/rxjs/drr.ts

@@ -1,11 +1,13 @@
-// Copyright 2017-2019 @polkadot/api-derive authors & contributors
+// Copyright 2017-2019 @polkadot/rpc-core authors & contributors
 // This software may be modified and distributed under the terms
 // of the Apache-2.0 license. See the LICENSE file for details.
 
-import { catchError, distinctUntilChanged, publishReplay, refCount } from 'rxjs/operators';
 import { Observable } from 'rxjs';
+import { catchError, distinctUntilChanged, publishReplay } from 'rxjs/operators';
 import { logger } from '@polkadot/util';
 
+import { refCountDelay } from './refCountDelay';
+
 type DrrResult = <T> (source$: Observable<T>) => Observable<T>;
 
 const l = logger('drr');
@@ -23,8 +25,8 @@ export const drr = (): DrrResult => <T> (source$: Observable<T>): Observable<T>
       throw error;
     }),
     distinctUntilChanged((a: any, b: any): boolean =>
-      JSON.stringify({ value: a }) === JSON.stringify({ value: b })
+      JSON.stringify({ t: a }) === JSON.stringify({ t: b })
     ),
     publishReplay(1),
-    refCount()
+    refCountDelay()
   );

packages/rpc-core/src/rxjs/index.ts

@@ -0,0 +1,6 @@
+// Copyright 2017-2019 @polkadot/rpc-core authors & contributors
+// This software may be modified and distributed under the terms
+// of the Apache-2.0 license. See the LICENSE file for details.
+
+export * from './drr';
+export * from './refCountDelay';

packages/rpc-core/src/rxjs/refCountDelay.ts

@@ -0,0 +1,55 @@
+// Copyright 2017-2019 @polkadot/rpc-core authors & contributors
+// This software may be modified and distributed under the terms
+// of the Apache-2.0 license. See the LICENSE file for details.
+
+// From https://medium.com/@volkeron/rxjs-unsubscribe-delay-218a9ab2672e (adapted for rxjs 6)
+// v6 inspiration from https://github.com/cartant/rxjs-etc/blob/7d7cd21233f67c364fd246ef72077bbe494dd5c2/source/operators/refCountDelay.ts
+
+import { asapScheduler, ConnectableObservable, MonoTypeOperatorFunction, NEVER, Observable, Subject, Subscription, timer, using } from 'rxjs';
+import { scan, switchMap, tap } from 'rxjs/operators';
+
+const DELAY = 1750;
+
+// subscribe to a source, tracker and increment the counter
+function subscribe <T> (source: Observable<T>, counter: Subject<number>, tracker: Observable<number>): [Subscription, Subscription] {
+  const sourceConn = (source as ConnectableObservable<T>).connect();
+  const trackerConn = tracker.subscribe();
+
+  counter.next(1);
+
+  return [sourceConn, trackerConn];
+}
+
+// unsubscribe from both the tracker and the source
+function unsubscribe (sourceConn: Subscription | undefined, trackerConn: Subscription | undefined): void {
+  sourceConn && sourceConn.unsubscribe();
+  trackerConn && trackerConn.unsubscribe();
+}
+
+// keep track of references, but only unsubscribe after the configured delay
+export function refCountDelay <T> (): MonoTypeOperatorFunction<T> {
+  return (source: Observable<T>): Observable<T> => {
+    let sourceConn: Subscription | undefined;
+    let trackerConn: Subscription | undefined;
+    const counter = new Subject<number>();
+    const tracker = counter.pipe(
+      scan((total, change) => change + total, 0),
+      switchMap((count) =>
+        count === 0 // when we have a zero count, schedule a unsubscribe
+          ? timer(DELAY, asapScheduler).pipe(tap((): void => unsubscribe(sourceConn, trackerConn)))
+          : NEVER
+      )
+    );
+
+    return using(
+      () => {
+        [sourceConn, trackerConn] = subscribe(source, counter, tracker);
+
+        return {
+          unsubscribe: (): void => counter.next(-1)
+        };
+      },
+      (): Observable<T> => source
+    );
+  };
+}