fix: asyncIterator typescript return type

Author: tjmehta

src/pubsub-async-iterator.ts

@@ -30,7 +30,10 @@ import { PubSubEngine } from 'graphql-subscriptions';
  * @property pubsub @type {PubSubEngine}
  * The PubSubEngine whose events will be observed.
  */
-export class PubSubAsyncIterator<T> implements AsyncIterator<T> {
+
+// eslint-disable-next-line @typescript-eslint/ban-ts-comment
+// @ts-ignore - https://github.com/leebyron/iterall/issues/49
+export class PubSubAsyncIterator<T> implements AsyncIterator<T>, AsyncIterable<T> {
 
   constructor(pubsub: PubSubEngine, eventNames: string | string[], options?: unknown) {
     this.pubsub = pubsub;
@@ -41,7 +44,7 @@ export class PubSubAsyncIterator<T> implements AsyncIterator<T> {
     this.eventsArray = typeof eventNames === 'string' ? [eventNames] : eventNames;
   }
 
-  public async next() {
+  public async next(): Promise<IteratorResult<T>> {
     await this.subscribeAll();
     return this.listening ? this.pullValue() : this.return();
   }
@@ -51,17 +54,17 @@ export class PubSubAsyncIterator<T> implements AsyncIterator<T> {
     return { value: undefined, done: true };
   }
 
-  public async throw(error): Promise<never> {
+  public async throw(error: Error): Promise<never> {
     await this.emptyQueue();
     return Promise.reject(error);
   }
 
-  public [$$asyncIterator]() {
+  public [$$asyncIterator](): AsyncIterator<T> {
     return this;
   }
 
-  private pullQueue: Array<(data: { value: unknown, done: boolean }) => void>;
-  private pushQueue: any[];
+  private pullQueue: Array<(data: { value: T, done: boolean }) => void>;
+  private pushQueue: T[];
   private eventsArray: string[];
   private subscriptionIds: Promise<number[]> | undefined;
   private listening: boolean;
@@ -77,7 +80,7 @@ export class PubSubAsyncIterator<T> implements AsyncIterator<T> {
     }
   }
 
-  private pullValue(): Promise<IteratorResult<any>> {
+  private pullValue(): Promise<IteratorResult<T>> {
     return new Promise(resolve => {
       if (this.pushQueue.length !== 0) {
         resolve({ value: this.pushQueue.shift(), done: false });

src/redis-pubsub.ts

@@ -1,6 +1,7 @@
 import {Cluster, Ok, Redis, RedisOptions} from 'ioredis';
-import {PubSubEngine} from 'graphql-subscriptions';
+
 import {PubSubAsyncIterator} from './pubsub-async-iterator';
+import {PubSubEngine} from 'graphql-subscriptions';
 
 type RedisClient = Redis | Cluster;
 type OnMessage<T> = (message: T) => void;
@@ -136,8 +137,9 @@ export class RedisPubSub implements PubSubEngine {
     delete this.subscriptionMap[subId];
   }
 
-  public asyncIterator<T>(triggers: string | string[], options?: unknown): AsyncIterator<T> {
-    return new PubSubAsyncIterator<T>(this, triggers, options);
+  // return type can be simplified after https://github.com/leebyron/iterall/issues/49 is resolved
+  public asyncIterator<T>(triggers: string | string[], options?: unknown): PubSubAsyncIterator<T> & AsyncIterator<T> & AsyncIterable<T> {
+    return new PubSubAsyncIterator<T>(this, triggers, options) as unknown as PubSubAsyncIterator<T> & AsyncIterator<T> & AsyncIterable<T>;
   }
 
   public getSubscriber(): RedisClient {

src/test/integration-tests.ts

@@ -1,13 +1,14 @@
 import * as chai from 'chai';
 import * as chaiAsPromised from 'chai-as-promised';
-import { mock } from 'simple-mock';
-import { parse, GraphQLSchema, GraphQLObjectType, GraphQLString, GraphQLFieldResolver } from 'graphql';
-import { isAsyncIterable } from 'iterall';
-import { subscribe } from 'graphql/subscription';
 
+import { GraphQLFieldResolver, GraphQLObjectType, GraphQLSchema, GraphQLString, parse } from 'graphql';
+
+import { Cluster } from 'ioredis';
 import { RedisPubSub } from '../redis-pubsub';
+import { isAsyncIterable } from 'iterall';
+import { mock } from 'simple-mock';
+import { subscribe } from 'graphql/subscription';
 import { withFilter } from '../with-filter';
-import { Cluster } from 'ioredis';
 
 chai.use(chaiAsPromised);
 const expect = chai.expect;

src/test/tests.ts

@@ -1,9 +1,12 @@
+import * as IORedis from 'ioredis';
 import * as chai from 'chai';
 import * as chaiAsPromised from 'chai-as-promised';
-import { spy, restore, stub } from 'simple-mock';
-import { isAsyncIterable } from 'iterall';
+
+import { restore, spy, stub } from 'simple-mock';
+
 import { RedisPubSub } from '../redis-pubsub';
-import * as IORedis from 'ioredis';
+import { doesNotMatch } from 'assert';
+import { isAsyncIterable } from 'iterall';
 
 chai.use(chaiAsPromised);
 const expect = chai.expect;
@@ -423,15 +426,27 @@ describe('RedisPubSub', () => {
 });
 
 describe('PubSubAsyncIterator', () => {
+  async function firstResult<T>(iterator: AsyncIterable<T>): Promise<T> {
+    for await (let result of iterator) {
+      return result
+    }
+  }
 
-  it('should expose valid asyncItrator for a specific event', () => {
+  it('should expose valid asyncItrator for a specific event', (done) => {
     const pubSub = new RedisPubSub(mockOptions);
     const eventName = 'test';
     const iterator = pubSub.asyncIterator(eventName);
     // tslint:disable-next-line:no-unused-expression
     expect(iterator).to.exist;
     // tslint:disable-next-line:no-unused-expression
     expect(isAsyncIterable(iterator)).to.be.true;
+
+    firstResult(iterator).then(result => {
+      expect(result).eql({ test: true })
+      done()
+    }).catch(done)
+
+    pubSub.publish(eventName, { test: true })
   });
 
   it('should trigger event on asyncIterator when published', done => {