rx-to-async-iterator

Convert RxJS Observable streams to async iterators

IMPORTANT: This library only supports RxJS 4.x.

Looking for RxJS 5.0+ support? Try rxjs-to-async-iterator. (Same name but replace 'rx' with 'rxjs'.)

This module is primarily intended for use in testing more complex RxJS-based async sequences, though that doesn't preclude other use cases.

It is intended for use with mocha for testing as modified by co-mocha for coroutine/generator support.

Installation

NPM

1npm install --save rx-to-async-iterator

Usage

1require('co-mocha');
2const Rx = require('rx');
3const chai = require('chai');
4const expect = chai.expect;
5require('to-async-iterator');
6  // Side effect: Adds methods to Rx.Observable prototype.
7
8describe('some examples', () => {
9  it('can verify that an Observable generates a predetermined sequence of values', function *() {
10    const iter = Rx.Observable.from([42, 45]).toAsyncIterator();
11
12    expect(yield iter.nextValue()).to.equal(42);
13      // Will throw if onError or onCompleted are produced.
14    expect(yield iter.nextValue()).to.equal(45);
15
16    yield iter.shouldComplete();
17      // Will throw if onNext or onError are produced.
18
19    iter.unsubscribe();
20      // Use this if ending the test before the Observable terminates and you
21      // want to ensure proper resource cleanup. This is not necessary if you
22      // reach an onComplete or onError state in a successful test.
23  });
24
25  it('has a shortcut form for an Observable that produces a single value', function *() {
26    expect(yield Rx.Observable.just(47).shouldGenerateOneValue()).to.equal(47);
27      // Will throw if any sequence other than onNext(47), onCompleted() is produced.
28  });
29
30  it('has a shortcut form for an Observable that produces no values', function *() {
31    expect(yield Rx.Observable.empty(47)).shouldBeEmpty();
32      // Will throw if onNext or onError are produced.
33  });
34
35  it('can verify that an Observable generates an error', function *() {
36    const iter = Rx.Observable.throw(new Error('expected failure')).toAsyncIterator();
37    expect((yield iter.shouldThrow()).message).to.equal('expected failure');
38  });
39
40  it('has a shortcut form for an Observable that only generates an Error', function *() {
41    const obs = Rx.Observable.throw(new Error('expect this fail'));
42    expect((yield obs.shouldThrow()).message).to.equal('expect this fail');
43  });
44});
45

License

MIT