Add .keys on storage entries (#2032)

* Add .keys on storage entries

* Pass isOptional to storage type unwrap

* Linked maps TS types

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

@@ -13,12 +13,7 @@ import { StorageKey } from '@polkadot/types';
 
 import { memo } from '../util';
 
-interface Mapped {
-  nominators: DeriveEraNominatorExposure;
-  validators: DeriveEraValidatorExposure;
-}
-
-function mapStakers (stakers: [StorageKey, Exposure][]): Mapped {
+function mapStakers (era: EraIndex, stakers: [StorageKey, Exposure][]): DeriveEraExposure {
   const nominators: DeriveEraNominatorExposure = {};
   const validators: DeriveEraValidatorExposure = {};
 
@@ -35,7 +30,7 @@ function mapStakers (stakers: [StorageKey, Exposure][]): Mapped {
     });
   });
 
-  return { nominators, validators };
+  return { era, nominators, validators };
 }
 
 export function erasExposure (api: ApiInterfaceRx): (withActive?: boolean | BN | number) => Observable<DeriveEraExposure[]> {
@@ -56,10 +51,9 @@ export function erasExposure (api: ApiInterfaceRx): (withActive?: boolean | BN |
         ])
       ),
       map(([eras, erasStakers]): DeriveEraExposure[] =>
-        eras.map((era, index): DeriveEraExposure => ({
-          era,
-          ...mapStakers(erasStakers[index])
-        }))
+        eras.map((era, index): DeriveEraExposure =>
+          mapStakers(era, erasStakers[index])
+        )
       )
     )
   );

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

@@ -3,7 +3,7 @@
 // of the Apache-2.0 license. See the LICENSE file for details.
 
 import { ApiInterfaceRx } from '@polkadot/api/types';
-import { AccountId, Exposure } from '@polkadot/types/interfaces';
+import { AccountId } from '@polkadot/types/interfaces';
 import { DeriveStakingValidators } from '../types';
 
 import { Observable, combineLatest, of } from 'rxjs';
@@ -16,11 +16,11 @@ function queryNextStakers (api: ApiInterfaceRx): Observable<AccountId[]> {
   // 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
   return api.derive.session.indexes().pipe(
-    switchMap(({ activeEra }): Observable<[StorageKey, Exposure][]> =>
-      api.query.staking.erasStakers.entries(activeEra.addn(1)).pipe(take(1))
+    switchMap(({ activeEra }): Observable<StorageKey[]> =>
+      api.query.staking.erasStakers.keys(activeEra.addn(1)).pipe(take(1))
     ),
-    map((entries): AccountId[] =>
-      entries.map(([key]): AccountId => key.args[1] as AccountId)
+    map((keys): AccountId[] =>
+      keys.map((key): AccountId => key.args[1] as AccountId)
     )
   );
 }