Account info derive (#1523)

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

@@ -6,3 +6,4 @@ export * from './idAndIndex';
 export * from './idToIndex';
 export * from './indexToId';
 export * from './indexes';
+export * from './info';

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

@@ -2,11 +2,11 @@
 // This software may be modified and distributed under the terms
 // of the Apache-2.0 license. See the LICENSE file for details.
 
+import { ApiInterfaceRx } from '@polkadot/api/types';
 import { AccountId, AccountIndex } from '@polkadot/types/interfaces';
 
 import { Observable } from 'rxjs';
 import { map, switchMap } from 'rxjs/operators';
-import { ApiInterfaceRx } from '@polkadot/api/types';
 import { ENUMSET_SIZE } from '@polkadot/types/primitive/Generic/AccountIndex';
 import { createType } from '@polkadot/types';
 

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

@@ -0,0 +1,41 @@
+// Copyright 2017-2019 @polkadot/api-derive 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 { ApiInterfaceRx } from '@polkadot/api/types';
+import { AccountId, Balance } from '@polkadot/types/interfaces';
+import { Codec } from '@polkadot/types/types';
+import { DeriveAccountInfo } from '../types';
+
+import { Observable, of } from 'rxjs';
+import { map } from 'rxjs/operators';
+import { Bytes, Option, u32 } from '@polkadot/types';
+import { u8aToString } from '@polkadot/util';
+
+import { drr } from '../util/drr';
+
+type Result = Option<[Bytes, Balance] & Codec>;
+
+function formatNickname (api: ApiInterfaceRx, result: Result): string | undefined {
+  return result.isSome
+    ? u8aToString(result.unwrap()[0]).substr(0, (api.consts.nicks.maxLength as u32).toNumber())
+    : undefined;
+}
+
+/**
+ * @name info
+ * @description Returns aux. info with regards to an  account, current that includes the nickname
+ */
+export function info (api: ApiInterfaceRx): (address?: AccountId | string | null) => Observable<DeriveAccountInfo> {
+  // TODO We would really like to pass in an Address or AccountIndex here as well
+  return (address?: AccountId | string | null): Observable<DeriveAccountInfo> => {
+    return address && api.query.nicks
+      ? api.query.nicks.nameOf<Result>(address).pipe(
+        map((result): DeriveAccountInfo => ({
+          nickname: formatNickname(api, result)
+        })),
+        drr()
+      )
+      : of({} as DeriveAccountInfo);
+  };
+}

packages/api-derive/src/types.ts

@@ -7,6 +7,10 @@ import { AccountId, Balance, BlockNumber, EraIndex, Exposure, Index, RewardDesti
 import BN from 'bn.js';
 import { u32 } from '@polkadot/types';
 
+export interface DeriveAccountInfo {
+  nickname?: string;
+}
+
 export interface DerivedBalances {
   accountId: AccountId;
   accountNonce: Index;