Fix derive.democracy.preimage signature (#2194)

packages/api-derive/src/democracy/preimage.ts

@@ -17,8 +17,8 @@ import { parseImage } from './util';
 type PreImage = Option<ITuple<[Bytes, AccountId, Balance, BlockNumber]>>;
 
 export function preimage (api: ApiInterfaceRx): (hash: Hash) => Observable<DeriveProposalImage | undefined> {
-  return memo((hashes: Hash[]): Observable<DeriveProposalImage | undefined> =>
-    api.query.democracy.preimages<PreImage>(hashes).pipe(
+  return memo((hash: Hash): Observable<DeriveProposalImage | undefined> =>
+    api.query.democracy.preimages<PreImage>(hash).pipe(
       map((imageOpt) => parseImage(api, imageOpt))
     )
   );

packages/api-derive/src/democracy/preimages.ts

@@ -20,9 +20,7 @@ export function preimages (api: ApiInterfaceRx): (hashes: Hash[]) => Observable<
   return memo((hashes: Hash[]): Observable<(DeriveProposalImage | undefined)[]> =>
     api.query.democracy.preimages.multi<PreImage>(hashes).pipe(
       map((images): (DeriveProposalImage | undefined)[] =>
-        images.map((imageOpt) =>
-          parseImage(api, imageOpt)
-        )
+        images.map((imageOpt) => parseImage(api, imageOpt))
       )
     )
   );