Small cleanups & consistency (#2151)

* Small cleanups & consistency

* Fixes

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

@@ -16,7 +16,7 @@ function retrievePointsPrev (api: ApiInterfaceRx, currentElected: AccountId[]):
       api.registry.createType('EraRewardPoints', {
         individual: new Map<AccountId, RewardPoint>(
           individual
-            .map((points): RewardPoint => api.registry.createType('RewardPoint', points))
+            .map((points) => api.registry.createType('RewardPoint', points))
             .map((points, index): [AccountId, RewardPoint] => [currentElected[index], points])
         ),
         total

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

@@ -18,9 +18,7 @@ export function electedInfo (api: ApiInterfaceRx): () => Observable<DeriveStakin
         combineLatest([
           of(nextElected),
           combineLatest(
-            nextElected.map((accountId): Observable<DeriveStakingQuery> =>
-              api.derive.staking.query(accountId)
-            )
+            nextElected.map((accountId) => api.derive.staking.query(accountId))
           )
         ])
       ),

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

@@ -5,6 +5,7 @@
 import { ApiInterfaceRx } from '@polkadot/api/types';
 import { ActiveEraInfo, EraIndex } from '@polkadot/types/interfaces';
 
+import BN from 'bn.js';
 import { Observable, of } from 'rxjs';
 import { map } from 'rxjs/operators';
 import { Option, u32 } from '@polkadot/types';
@@ -21,7 +22,7 @@ export function erasHistoric (api: ApiInterfaceRx): (withActive?: boolean) => Ob
         map(([activeEraOpt, historyDepth]): EraIndex[] => {
           const result: EraIndex[] = [];
           const max = historyDepth.toNumber();
-          const activeEra = activeEraOpt.unwrapOrDefault().index.toBn();
+          const activeEra: BN = activeEraOpt.unwrapOrDefault().index;
           let lastEra = activeEra;
 
           while (lastEra.gten(0) && (result.length < max)) {

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

@@ -29,9 +29,7 @@ export function ownSlashes (api: ApiInterfaceRx): (accountId: Uint8Array | strin
           era,
           total: optVal.isSome
             ? optVal.unwrap()[1]
-            : optNom.isSome
-              ? optNom.unwrap()
-              : api.registry.createType('Balance')
+            : optNom.unwrapOrDefault()
         }))
       )
     );

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

@@ -3,7 +3,7 @@
 // of the Apache-2.0 license. See the LICENSE file for details.
 
 import { ApiInterfaceRx } from '@polkadot/api/types';
-import { DeriveStakerExposure, DeriveEraExposureNominating, DeriveEraValidatorExposure } from '../types';
+import { DeriveStakerExposure, DeriveEraValidatorExposure } from '../types';
 
 import { Observable } from 'rxjs';
 import { map } from 'rxjs/operators';
@@ -19,13 +19,11 @@ export function stakerExposure (api: ApiInterfaceRx): (accountId: Uint8Array | s
         exposures.map(({ era, nominators: allNominators, validators: allValidators }): DeriveStakerExposure => {
           const isValidator = !!allValidators[stakerId];
           const validators: DeriveEraValidatorExposure = {};
-          let nominating: DeriveEraExposureNominating[] = [];
+          const nominating = allNominators[stakerId] || [];
 
           if (isValidator) {
             validators[stakerId] = allValidators[stakerId];
-          } else if (allNominators[stakerId]) {
-            nominating = allNominators[stakerId];
-
+          } else if (nominating) {
             nominating.forEach(({ validatorId }): void => {
               validators[validatorId] = allValidators[validatorId];
             });

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

@@ -19,9 +19,7 @@ export function stakerPoints (api: ApiInterfaceRx): (accountId: Uint8Array | str
         points.map(({ era, eraPoints, validators }): DeriveStakerPoints => ({
           era,
           eraPoints,
-          points: validators[stakerId]
-            ? validators[stakerId]
-            : api.registry.createType('RewardPoint')
+          points: validators[stakerId] || api.registry.createType('RewardPoint')
         }))
       )
     );

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

@@ -8,7 +8,6 @@ import { DeriveStakingValidators } from '../types';
 
 import { Observable, combineLatest, of } from 'rxjs';
 import { map, switchMap } from 'rxjs/operators';
-import { StorageKey } from '@polkadot/types';
 
 import { memo } from '../util';
 
@@ -18,9 +17,7 @@ export function nextElected (api: ApiInterfaceRx): () => Observable<AccountId[]>
       ? api.derive.session.indexes().pipe(
         // only populate for next era in the last session, so track both here - entries are not
         // subscriptions, so we need a trigger - currentIndex acts as that trigger to refresh
-        switchMap(({ currentEra }): Observable<StorageKey[]> =>
-          api.query.staking.erasStakers.keys(currentEra)
-        ),
+        switchMap(({ currentEra }) => api.query.staking.erasStakers.keys(currentEra)),
         map((keys): AccountId[] =>
           keys.map((key): AccountId => key.args[1] as AccountId)
         )