spec-js/operators/takeWhile-spec.js

"use strict";
var chai_1 = require('chai');
var Rx = require('../../dist/cjs/Rx');
var Observable = Rx.Observable;
/** @test {takeWhile} */
describe('Observable.prototype.takeWhile', function () {
    asDiagram('takeWhile(x => x < 4)')('should take all elements until predicate is false', function () {
        var source = hot('-1-^2--3--4--5--6--|');
        var sourceSubs = '^      !         ';
        var expected = '-2--3--|         ';
        var result = source.takeWhile(function (v) { return +v < 4; });
        expectObservable(result).toBe(expected);
        expectSubscriptions(source.subscriptions).toBe(sourceSubs);
    });
    it('should take all elements with predicate returns true', function () {
        var e1 = hot('--a-^-b--c--d--e--|');
        var e1subs = '^             !';
        var expected = '--b--c--d--e--|';
        expectObservable(e1.takeWhile(function () { return true; })).toBe(expected);
        expectSubscriptions(e1.subscriptions).toBe(e1subs);
    });
    it('should take all elements with truthy predicate', function () {
        var e1 = hot('--a-^-b--c--d--e--|');
        var e1subs = '^             !';
        var expected = '--b--c--d--e--|';
        expectObservable(e1.takeWhile((function () { return {}; }))).toBe(expected);
        expectSubscriptions(e1.subscriptions).toBe(e1subs);
    });
    it('should skip all elements with predicate returns false', function () {
        var e1 = hot('--a-^-b--c--d--e--|');
        var e1subs = '^ !            ';
        var expected = '--|            ';
        expectObservable(e1.takeWhile(function () { return false; })).toBe(expected);
        expectSubscriptions(e1.subscriptions).toBe(e1subs);
    });
    it('should skip all elements with falsy predicate', function () {
        var e1 = hot('--a-^-b--c--d--e--|');
        var e1subs = '^ !            ';
        var expected = '--|            ';
        expectObservable(e1.takeWhile(function () { return null; })).toBe(expected);
        expectSubscriptions(e1.subscriptions).toBe(e1subs);
    });
    it('should take all elements until predicate return false', function () {
        var e1 = hot('--a-^-b--c--d--e--|');
        var e1subs = '^       !      ';
        var expected = '--b--c--|      ';
        function predicate(value) {
            return value !== 'd';
        }
        expectObservable(e1.takeWhile(predicate)).toBe(expected);
        expectSubscriptions(e1.subscriptions).toBe(e1subs);
    });
    it('should take elements with predicate when source does not complete', function () {
        var e1 = hot('--a-^-b--c--d--e--');
        var e1subs = '^             ';
        var expected = '--b--c--d--e--';
        expectObservable(e1.takeWhile(function () { return true; })).toBe(expected);
        expectSubscriptions(e1.subscriptions).toBe(e1subs);
    });
    it('should not complete when source never completes', function () {
        var e1 = cold('-');
        var e1subs = '^';
        var expected = '-';
        var result = e1.takeWhile(function () { return true; });
        expectObservable(result).toBe(expected);
        expectSubscriptions(e1.subscriptions).toBe(e1subs);
    });
    it('should complete when source does not emit', function () {
        var e1 = hot('--a-^------------|');
        var e1subs = '^            !';
        var expected = '-------------|';
        expectObservable(e1.takeWhile(function () { return true; })).toBe(expected);
        expectSubscriptions(e1.subscriptions).toBe(e1subs);
    });
    it('should complete when source is empty', function () {
        var e1 = cold('|');
        var e1subs = '(^!)';
        var expected = '|';
        var result = e1.takeWhile(function () { return true; });
        expectObservable(result).toBe(expected);
        expectSubscriptions(e1.subscriptions).toBe(e1subs);
    });
    it('should pass element index to predicate', function () {
        var e1 = hot('--a-^-b--c--d--e--|');
        var e1subs = '^       !      ';
        var expected = '--b--c--|      ';
        function predicate(value, index) {
            return index < 2;
        }
        expectObservable(e1.takeWhile(predicate)).toBe(expected);
        expectSubscriptions(e1.subscriptions).toBe(e1subs);
    });
    it('should raise error when source raises error', function () {
        var e1 = hot('--a-^-b--c--d--e--#');
        var e1subs = '^             !';
        var expected = '--b--c--d--e--#';
        expectObservable(e1.takeWhile(function () { return true; })).toBe(expected);
        expectSubscriptions(e1.subscriptions).toBe(e1subs);
    });
    it('should raise error when source throws', function () {
        var source = cold('#');
        var subs = '(^!)';
        var expected = '#';
        expectObservable(source.takeWhile(function () { return true; })).toBe(expected);
        expectSubscriptions(source.subscriptions).toBe(subs);
    });
    it('should invoke predicate until return false', function () {
        var e1 = hot('--a-^-b--c--d--e--|');
        var e1subs = '^       !      ';
        var expected = '--b--c--|      ';
        var invoked = 0;
        function predicate(value) {
            invoked++;
            return value !== 'd';
        }
        var source = e1.takeWhile(predicate).do(null, null, function () {
            chai_1.expect(invoked).to.equal(3);
        });
        expectObservable(source).toBe(expected);
        expectSubscriptions(e1.subscriptions).toBe(e1subs);
    });
    it('should raise error if predicate throws', function () {
        var e1 = hot('--a-^-b--c--d--e--|');
        var e1subs = '^ !            ';
        var expected = '--#            ';
        function predicate(value) {
            throw 'error';
        }
        expectObservable(e1.takeWhile(predicate)).toBe(expected);
        expectSubscriptions(e1.subscriptions).toBe(e1subs);
    });
    it('should take elements until unsubscribed', function () {
        var e1 = hot('--a-^-b--c--d--e--|');
        var unsub = '-----!         ';
        var e1subs = '^    !         ';
        var expected = '--b---         ';
        function predicate(value) {
            return value !== 'd';
        }
        expectObservable(e1.takeWhile(predicate), unsub).toBe(expected);
        expectSubscriptions(e1.subscriptions).toBe(e1subs);
    });
    it('should not break unsubscription chain when unsubscribed explicitly', function () {
        var e1 = hot('--a-^-b--c--d--e--|');
        var unsub = '-----!         ';
        var e1subs = '^    !         ';
        var expected = '--b---         ';
        function predicate(value) {
            return value !== 'd';
        }
        var result = e1
            .mergeMap(function (x) { return Observable.of(x); })
            .takeWhile(predicate)
            .mergeMap(function (x) { return Observable.of(x); });
        expectObservable(result, unsub).toBe(expected);
        expectSubscriptions(e1.subscriptions).toBe(e1subs);
    });
});
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