Rework eras* calls with minimum information (#2018)

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

@@ -1,39 +0,0 @@
-// 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 { Exposure } from '@polkadot/types/interfaces';
-import { DeriveEraRewardsAll } from '../types';
-
-import { Observable } from 'rxjs';
-import { map } from 'rxjs/operators';
-
-import { memo } from '../util';
-
-function includeExposure (validatorId: string, { others }: Exposure, nominators: Record<string, [string, number][]>): void {
-  others.forEach(({ who }, index): void => {
-    const nominatorId = who.toString();
-
-    nominators[nominatorId] = nominators[nominatorId] || [];
-    nominators[nominatorId].push([validatorId, index]);
-  });
-}
-
-export function erasRewards (api: ApiInterfaceRx): (withActive?: boolean) => Observable<DeriveEraRewardsAll[]> {
-  return memo((withActive?: boolean): Observable<DeriveEraRewardsAll[]> =>
-    api.derive.staking.erasExposure(withActive).pipe(
-      map((exposures): DeriveEraRewardsAll[] =>
-        exposures.map(({ era, eraPoints, eraReward, validators }): DeriveEraRewardsAll =>
-          Object
-            .entries(validators)
-            .reduce((rewards: DeriveEraRewardsAll, [validatorId, { exposure }]): DeriveEraRewardsAll => {
-              includeExposure(validatorId, exposure, rewards.nominators);
-
-              return rewards;
-            }, { era, eraPoints, eraReward, nominators: {}, validators })
-        )
-      )
-    )
-  );
-}