Move indices cache to indices list (#2390)

packages/api-derive/src/accounts/idToIndex.ts

@@ -5,14 +5,12 @@
 import { AccountId, AccountIndex } from '@polkadot/types/interfaces';
 import { AccountIndexes } from '../types';
 
-import { Observable, of } from 'rxjs';
+import { Observable } from 'rxjs';
 import { map } from 'rxjs/operators';
 import { ApiInterfaceRx } from '@polkadot/api/types';
 
 import { memo } from '../util';
 
-const cached = new Map<string, AccountIndex>();
-
 /**
  * @name idToIndex
  * @param {( AccountId | string )} accountId - An accounts Id in different formats.
@@ -28,19 +26,10 @@ const cached = new Map<string, AccountIndex>();
  * ```
  */
 export function idToIndex (api: ApiInterfaceRx): (accountId: AccountId | string) => Observable<AccountIndex | undefined> {
-  return memo((accountId: AccountId | string): Observable<AccountIndex | undefined> => {
-    const address = accountId.toString();
-
-    if (cached.has(address)) {
-      return of(cached.get(address));
-    }
-
-    return api.derive.accounts.indexes().pipe(
-      map((indexes: AccountIndexes): AccountIndex | undefined => {
-        Object.entries(indexes).forEach(([address, index]) => cached.set(address, index));
-
-        return cached.get(address);
-      })
-    );
-  });
+  return memo((accountId: AccountId | string): Observable<AccountIndex | undefined> =>
+    api.derive.accounts.indexes().pipe(
+      map((indexes: AccountIndexes): AccountIndex | undefined =>
+        (indexes || {})[accountId.toString()]
+      )
+    ));
 }

packages/api-derive/src/accounts/indexes.ts

@@ -16,6 +16,8 @@ import { memo } from '../util';
 
 const enumsetSize = ENUMSET_SIZE.toNumber();
 
+let indicesCache: AccountIndexes | null = null;
+
 function queryEnumSet (api: ApiInterfaceRx): Observable<AccountIndexes> {
   return api.query.indices.nextEnumSet<AccountIndex>().pipe(
     // use the nextEnumSet (which is a counter of the number of sets) to construct
@@ -72,11 +74,20 @@ function queryAccounts (api: ApiInterfaceRx): Observable<AccountIndexes> {
  */
 export function indexes (api: ApiInterfaceRx): () => Observable<AccountIndexes> {
   return memo((): Observable<AccountIndexes> =>
-    (api.query.indices
-      ? isFunction(api.query.indices.accounts)
-        ? queryAccounts(api)
-        : queryEnumSet(api)
-      : of({} as AccountIndexes)
-    ).pipe(startWith({}))
+    indicesCache
+      ? of(indicesCache)
+      : (
+        api.query.indices
+          ? isFunction(api.query.indices.accounts)
+            ? queryAccounts(api).pipe(startWith({}))
+            : queryEnumSet(api).pipe(startWith({}))
+          : of({} as AccountIndexes)
+      ).pipe(
+        map((indices): AccountIndexes => {
+          indicesCache = indices;
+
+          return indices;
+        })
+      )
   );
 }