@reactivex/rxjs/spec-js/observables/defer-spec.js

Reactive Extensions for modern JavaScript

"use strict";
var chai_1 = require('chai');
var Rx = require('../../dist/cjs/Rx');
var Observable = Rx.Observable;
/** @test {defer} */
describe('Observable.defer', function () {
    asDiagram('defer(() => Observable.of(a, b, c))')('should defer the creation of a simple Observable', function () {
        var expected = '-a--b--c--|';
        var e1 = Observable.defer(function () { return cold('-a--b--c--|'); });
        expectObservable(e1).toBe(expected);
    });
    it('should create an observable from the provided observable factory', function () {
        var source = hot('--a--b--c--|');
        var sourceSubs = '^          !';
        var expected = '--a--b--c--|';
        var e1 = Observable.defer(function () { return source; });
        expectObservable(e1).toBe(expected);
        expectSubscriptions(source.subscriptions).toBe(sourceSubs);
    });
    it('should create an observable from completed', function () {
        var source = hot('|');
        var sourceSubs = '(^!)';
        var expected = '|';
        var e1 = Observable.defer(function () { return source; });
        expectObservable(e1).toBe(expected);
        expectSubscriptions(source.subscriptions).toBe(sourceSubs);
    });
    it('should accept factory returns promise resolves', function (done) {
        var expected = 42;
        var e1 = Observable.defer(function () {
            return new Promise(function (resolve) { resolve(expected); });
        });
        e1.subscribe(function (x) {
            chai_1.expect(x).to.equal(expected);
            done();
        }, function (x) {
            done(new Error('should not be called'));
        });
    });
    it('should accept factory returns promise rejects', function (done) {
        var expected = 42;
        var e1 = Observable.defer(function () {
            return new Promise(function (resolve, reject) { reject(expected); });
        });
        e1.subscribe(function (x) {
            done(new Error('should not be called'));
        }, function (x) {
            chai_1.expect(x).to.equal(expected);
            done();
        }, function () {
            done(new Error('should not be called'));
        });
    });
    it('should create an observable from error', function () {
        var source = hot('#');
        var sourceSubs = '(^!)';
        var expected = '#';
        var e1 = Observable.defer(function () { return source; });
        expectObservable(e1).toBe(expected);
        expectSubscriptions(source.subscriptions).toBe(sourceSubs);
    });
    it('should create an observable when factory throws', function () {
        var e1 = Observable.defer(function () {
            throw 'error';
        });
        var expected = '#';
        expectObservable(e1).toBe(expected);
    });
    it('should allow unsubscribing early and explicitly', function () {
        var source = hot('--a--b--c--|');
        var sourceSubs = '^     !     ';
        var expected = '--a--b-     ';
        var unsub = '      !     ';
        var e1 = Observable.defer(function () { return source; });
        expectObservable(e1, unsub).toBe(expected);
        expectSubscriptions(source.subscriptions).toBe(sourceSubs);
    });
    it('should not break unsubscription chains when result is unsubscribed explicitly', function () {
        var source = hot('--a--b--c--|');
        var sourceSubs = '^     !     ';
        var expected = '--a--b-     ';
        var unsub = '      !     ';
        var e1 = Observable.defer(function () { return source.mergeMap(function (x) { return Observable.of(x); }); })
            .mergeMap(function (x) { return Observable.of(x); });
        expectObservable(e1, unsub).toBe(expected);
        expectSubscriptions(source.subscriptions).toBe(sourceSubs);
    });
});
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