Add derive.staking.waitingInfo (#2367)

* Add derive.staking.waitingInfo

* Small optimizations

* Updated

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

@@ -3,10 +3,9 @@
 // of the Apache-2.0 license. See the LICENSE file for details.
 
 import { ApiInterfaceRx } from '@polkadot/api/types';
-import { AccountId } from '@polkadot/types/interfaces';
-import { DeriveStakingQuery, DeriveStakingElected } from '../types';
+import { DeriveStakingElected } from '../types';
 
-import { Observable, combineLatest, of } from 'rxjs';
+import { Observable, combineLatest } from 'rxjs';
 import { map, switchMap } from 'rxjs/operators';
 
 import { memo } from '../util';
@@ -14,18 +13,16 @@ import { memo } from '../util';
 export function electedInfo (api: ApiInterfaceRx): () => Observable<DeriveStakingElected> {
   return memo((): Observable<DeriveStakingElected> =>
     api.derive.staking.validators().pipe(
-      switchMap(({ nextElected }): Observable<[AccountId[], DeriveStakingQuery[]]> =>
-        combineLatest([
-          of(nextElected),
-          combineLatest(
-            nextElected.map((accountId) => api.derive.staking.query(accountId))
-          )
-        ])
-      ),
-      map(([nextElected, info]): DeriveStakingElected => ({
-        info,
-        nextElected
-      }))
+      switchMap(({ nextElected }): Observable<DeriveStakingElected> =>
+        combineLatest(
+          nextElected.map((accountId) => api.derive.staking.query(accountId))
+        ).pipe(
+          map((info): DeriveStakingElected => ({
+            info,
+            nextElected
+          }))
+        )
+      )
     )
   );
 }

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

@@ -21,3 +21,4 @@ export * from './stakerRewards';
 export * from './stakerSlashes';
 export * from './stashes';
 export * from './validators';
+export * from './waitingInfo';

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

@@ -96,6 +96,11 @@ export interface DeriveStakingElected {
   info: DeriveStakingQuery[];
 }
 
+export interface DeriveStakingWaiting {
+  info: DeriveStakingQuery[];
+  waiting: AccountId[];
+}
+
 export interface DeriveStakingValidators {
   nextElected: AccountId[];
   validators: AccountId[];

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

@@ -0,0 +1,34 @@
+// Copyright 2017-2020 @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 { DeriveStakingWaiting } from '../types';
+
+import { Observable, combineLatest } from 'rxjs';
+import { map, switchMap } from 'rxjs/operators';
+
+import { memo } from '../util';
+
+export function waitingInfo (api: ApiInterfaceRx): () => Observable<DeriveStakingWaiting> {
+  return memo((): Observable<DeriveStakingWaiting> =>
+    combineLatest([
+      api.derive.staking.validators(),
+      api.derive.staking.stashes()
+    ]).pipe(
+      switchMap(([{ nextElected }, stashes]): Observable<DeriveStakingWaiting> => {
+        const elected = nextElected.map((a) => a.toString());
+        const waiting = stashes.filter((v) => !elected.includes(v.toString()));
+
+        return combineLatest(
+          waiting.map((accountId) => api.derive.staking.query(accountId))
+        ).pipe(
+          map((info): DeriveStakingWaiting => ({
+            info,
+            waiting
+          }))
+        );
+      })
+    )
+  );
+}