Handle storage with optional modifiers (#717)

* Handle storage with optional modifiers

* Storage docs indicate Option

* Cleanup Option logic

* Convert Optional derive to use Option

* Bump version, update changelog

* Update CHANGELOG description

* Enum.spec.js -> Enum.spec.ts

* Add isEmpty to primitive types

packages/api-derive/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@polkadot/api-derive",
-  "version": "0.44.1",
+  "version": "0.45.0",
   "description": "Common functions used across Polkadot, derived from RPC calls and storage queries.",
   "main": "index.js",
   "keywords": [
@@ -31,8 +31,8 @@
   "homepage": "https://github.com/polkadot-js/api/tree/master/packages/api-derive#readme",
   "dependencies": {
     "@babel/runtime": "^7.3.1",
-    "@polkadot/api": "^0.44.1",
-    "@polkadot/types": "^0.44.1",
+    "@polkadot/api": "^0.45.0",
+    "@polkadot/types": "^0.45.0",
     "@types/memoizee": "^0.4.2",
     "memoizee": "^0.4.14"
   }

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

@@ -6,7 +6,7 @@ import BN from 'bn.js';
 import { Observable } from 'rxjs';
 import { map } from 'rxjs/operators';
 import { ApiInterface$Rx } from '@polkadot/api/types';
-import { ReferendumInfo, ReferendumIndex } from '@polkadot/types/index';
+import { Option, ReferendumInfo, ReferendumIndex } from '@polkadot/types/index';
 
 import { drr } from '../util/drr';
 
@@ -16,27 +16,32 @@ import { drr } from '../util/drr';
  * A [[ReferendumInfo]] with an additional `index` field
  */
 export class ReferendumInfoExtended extends ReferendumInfo {
-  private _index: ReferendumIndex;
-
-  constructor (info: ReferendumInfo, index: BN | number) {
+  constructor (info: any) {
     super(info);
 
-    this._index = new ReferendumIndex(index);
+    this.set('index', new ReferendumIndex(info.index));
   }
 
   /**
    * @description Convenience getter, returns the referendumIndex
    */
   get index (): ReferendumIndex {
-    return this._index;
+    return this.get('index') as ReferendumIndex;
   }
 }
 
 export function referendumInfo (api: ApiInterface$Rx) {
-  return (id: BN | number): Observable<ReferendumInfoExtended> => {
-    return (api.query.democracy.referendumInfoOf(id) as Observable<ReferendumInfo>)
+  return (index: BN | number): Observable<Option<ReferendumInfoExtended>> => {
+    return (api.query.democracy.referendumInfoOf(index) as Observable<Option<ReferendumInfo>>)
       .pipe(
-        map((info) => new ReferendumInfoExtended(info, id)),
+        map((info) =>
+          new Option<ReferendumInfoExtended>(
+            ReferendumInfoExtended,
+            info.isSome
+              ? { ...info.toJSON(), index }
+              : null
+          )
+        ),
         drr()
       );
   };

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

@@ -5,6 +5,7 @@
 import BN from 'bn.js';
 import { combineLatest, Observable, of } from 'rxjs';
 import { ApiInterface$Rx } from '@polkadot/api/types';
+import { Option } from '@polkadot/types/index';
 
 import { drr } from '../util/drr';
 import { referendumInfo, ReferendumInfoExtended } from './referendumInfo';
@@ -12,7 +13,7 @@ import { referendumInfo, ReferendumInfoExtended } from './referendumInfo';
 export function referendumInfos (api: ApiInterface$Rx) {
   const referendumInfoOf = referendumInfo(api);
 
-  return (ids: Array<BN | number> = []): Observable<Array<ReferendumInfoExtended>> => {
+  return (ids: Array<BN | number> = []): Observable<Array<Option<ReferendumInfoExtended>>> => {
     return !ids || !ids.length
       ? of([]).pipe(drr())
       : combineLatest(

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

@@ -5,14 +5,14 @@
 import { combineLatest, Observable, of } from 'rxjs';
 import { switchMap } from 'rxjs/operators';
 import { ApiInterface$Rx } from '@polkadot/api/types';
-import { ReferendumIndex } from '@polkadot/types/index';
+import { Option, ReferendumIndex } from '@polkadot/types/index';
 
 import { drr } from '../util/drr';
 import { ReferendumInfoExtended } from './referendumInfo';
 import { referendumInfos } from './referendumInfos';
 
 export function referendums (api: ApiInterface$Rx) {
-  return (): Observable<Array<ReferendumInfoExtended>> =>
+  return (): Observable<Array<Option<ReferendumInfoExtended>>> =>
     (combineLatest(
       api.query.democracy.nextTally(),
       api.query.democracy.referendumCount()

packages/api-derive/src/session/sessionProgress.ts

@@ -6,7 +6,7 @@ import BN from 'bn.js';
 import { combineLatest, Observable } from 'rxjs';
 import { map } from 'rxjs/operators';
 import { ApiInterface$Rx } from '@polkadot/api/types';
-import { BlockNumber } from '@polkadot/types/index';
+import { BlockNumber, Option } from '@polkadot/types/index';
 
 import { bestNumber } from '../chain';
 import { drr } from '../util/drr';
@@ -21,7 +21,7 @@ export function sessionProgress (api: ApiInterface$Rx) {
       map(
         ([bestNumber, sessionLength, lastLengthChange]) =>
           (bestNumber || new BN(0))
-            .sub(lastLengthChange as BlockNumber || new BN(0))
+            .sub((lastLengthChange as Option<BlockNumber>).unwrapOr(new BN(0)))
             .add(sessionLength as BlockNumber || new BN(1))
             .mod(sessionLength as BlockNumber || new BN(1))
       ),