Collective dedupe (#4319)

Author: jacogr

packages/api-derive/src/collective/helpers.ts

@@ -1,9 +1,16 @@
 // Copyright 2017-2021 @polkadot/api-derive authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
+import type { Observable } from 'rxjs';
 import type { ApiInterfaceRx } from '@polkadot/api/types';
 import type { Collective } from './types';
 
+import { of } from 'rxjs';
+
+import { isFunction } from '@polkadot/util';
+
+import { memo } from '../util';
+
 // We are re-exporting these from here to ensure that *.d.ts generation is correct
 export type { ApiInterfaceRx } from '@polkadot/api/types';
 
@@ -19,3 +26,14 @@ export function withSection <T> (_section: Collective, fn: (section: string, ins
   return (instanceId: string, api: ApiInterfaceRx) =>
     fn(getInstance(api, _section), instanceId, api);
 }
+
+export function callMethod <T> (method: 'members' | 'proposals' | 'proposalCount', empty: T): (_section: Collective) => (instanceId: string, api: ApiInterfaceRx) => () => Observable<T> {
+  return (_section: Collective) =>
+    withSection(_section, (section, instanceId, api) =>
+      memo(instanceId, (): Observable<T> =>
+        isFunction(api.query[section]?.[method])
+          ? api.query[section as 'council'][method]() as unknown as Observable<T>
+          : of(empty)
+      )
+    );
+}

packages/api-derive/src/collective/members.ts

@@ -1,28 +1,11 @@
 // Copyright 2017-2021 @polkadot/api-derive authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
-import type { Observable } from 'rxjs';
-import type { ApiInterfaceRx } from '@polkadot/api/types';
 import type { AccountId } from '@polkadot/types/interfaces';
-import type { Collective } from './types';
 
-import { of } from 'rxjs';
-
-import { isFunction } from '@polkadot/util';
-
-import { memo } from '../util';
-import { withSection } from './helpers';
+import { callMethod } from './helpers';
 
 // We are re-exporting these from here to ensure that *.d.ts generation is correct
-export type { ApiInterfaceRx } from '@polkadot/api/types';
 export type { AccountId } from '@polkadot/types/interfaces';
 
-export function members (_section: Collective): (instanceId: string, api: ApiInterfaceRx) => () => Observable<AccountId[]> {
-  return withSection(_section, (section, instanceId, api) =>
-    memo(instanceId, (): Observable<AccountId[]> =>
-      isFunction(api.query[section]?.members)
-        ? api.query[section as 'council'].members()
-        : of([])
-    )
-  );
-}
+export const members = callMethod<AccountId[]>('members', []);

packages/api-derive/src/collective/proposals.ts

@@ -13,7 +13,7 @@ import { catchError, combineLatest, map, of, switchMap } from 'rxjs';
 import { isFunction } from '@polkadot/util';
 
 import { memo } from '../util';
-import { withSection } from './helpers';
+import { callMethod, withSection } from './helpers';
 
 // We are re-exporting these from here to ensure that *.d.ts generation is correct
 export type { ApiInterfaceRx } from '@polkadot/api/types';
@@ -72,26 +72,6 @@ export function hasProposals (_section: Collective): (instanceId: string, api: A
   );
 }
 
-export function proposalCount (_section: Collective): (instanceId: string, api: ApiInterfaceRx) => () => Observable<u32 | null> {
-  return withSection(_section, (section, instanceId, api) =>
-    memo(instanceId, (): Observable<u32 | null> =>
-      isFunction(api.query[section].proposalCount)
-        ? api.query[section as 'council'].proposalCount()
-        : of(null)
-    )
-  );
-}
-
-export function proposalHashes (_section: Collective): (instanceId: string, api: ApiInterfaceRx) => () => Observable<Hash[]> {
-  return withSection(_section, (section, instanceId, api) =>
-    memo(instanceId, (): Observable<Hash[]> =>
-      isFunction(api.query[section]?.proposals)
-        ? api.query[section as 'council'].proposals()
-        : of([])
-    )
-  );
-}
-
 export function proposals (_section: Collective): (instanceId: string, api: ApiInterfaceRx) => () => Observable<DeriveCollectiveProposal[]> {
   return withProposals(_section, (section, instanceId, api, proposalsFrom) =>
     memo(instanceId, (): Observable<DeriveCollectiveProposal[]> =>
@@ -113,3 +93,6 @@ export function proposal (_section: Collective): (instanceId: string, api: ApiIn
     )
   );
 }
+
+export const proposalCount = callMethod<u32 | null>('proposalCount', null);
+export const proposalHashes = callMethod<Hash[]>('proposals', []);