spec-js/operators/last-spec.js

"use strict";
var chai_1 = require('chai');
var Rx = require('../../dist/cjs/Rx');
/** @test {last} */
describe('Observable.prototype.last', function () {
    asDiagram('last')('should take the last value of an observable', function () {
        var e1 = hot('--a----b--c--|');
        var e1subs = '^            !';
        var expected = '-------------(c|)';
        expectObservable(e1.last()).toBe(expected);
        expectSubscriptions(e1.subscriptions).toBe(e1subs);
    });
    it('should error on nothing sent but completed', function () {
        var e1 = hot('--a--^----|');
        var e1subs = '^    !';
        var expected = '-----#';
        expectObservable(e1.last()).toBe(expected, null, new Rx.EmptyError());
        expectSubscriptions(e1.subscriptions).toBe(e1subs);
    });
    it('should error on empty', function () {
        var e1 = cold('|');
        var e1subs = '(^!)';
        var expected = '#';
        expectObservable(e1.last()).toBe(expected, null, new Rx.EmptyError());
        expectSubscriptions(e1.subscriptions).toBe(e1subs);
    });
    it('should go on forever on never', function () {
        var e1 = cold('-');
        var e1subs = '^';
        var expected = '-';
        expectObservable(e1.last()).toBe(expected);
        expectSubscriptions(e1.subscriptions).toBe(e1subs);
    });
    it('should return last element matches with predicate', function () {
        var e1 = hot('--a--b--a--b--|');
        var e1subs = '^             !';
        var expected = '--------------(b|)';
        var predicate = function (value) {
            return value === 'b';
        };
        expectObservable(e1.last(predicate)).toBe(expected);
        expectSubscriptions(e1.subscriptions).toBe(e1subs);
    });
    it('should allow unsubscribing explicitly and early', function () {
        var e1 = hot('--a--b--c--d--|');
        var unsub = '       !       ';
        var e1subs = '^      !       ';
        var expected = '--------       ';
        expectObservable(e1.last(), unsub).toBe(expected);
        expectSubscriptions(e1.subscriptions).toBe(e1subs);
    });
    it('should not break unsubscription chains when result is unsubscribed explicitly', function () {
        var e1 = hot('--a--b--c--d--|');
        var e1subs = '^      !       ';
        var expected = '--------       ';
        var unsub = '       !       ';
        var result = e1
            .mergeMap(function (x) { return Rx.Observable.of(x); })
            .last()
            .mergeMap(function (x) { return Rx.Observable.of(x); });
        expectObservable(result, unsub).toBe(expected);
        expectSubscriptions(e1.subscriptions).toBe(e1subs);
    });
    it('should return a default value if no element found', function () {
        var e1 = cold('|');
        var e1subs = '(^!)';
        var expected = '(a|)';
        expectObservable(e1.last(null, null, 'a')).toBe(expected);
        expectSubscriptions(e1.subscriptions).toBe(e1subs);
    });
    it('should not return default value if an element is found', function () {
        var e1 = hot('--a---^---b---c---d---|');
        var e1subs = '^               !';
        var expected = '----------------(d|)';
        expectObservable(e1.last(null, null, 'x')).toBe(expected);
        expectSubscriptions(e1.subscriptions).toBe(e1subs);
    });
    it('should support a result selector argument', function () {
        var e1 = hot('--a--^---b---c---d---e--|');
        var e1subs = '^                  !';
        var expected = '-------------------(x|)';
        var predicate = function (x) { return x === 'c'; };
        var resultSelector = function (x, i) {
            chai_1.expect(i).to.equal(1);
            chai_1.expect(x).to.equal('c');
            return 'x';
        };
        expectObservable(e1.last(predicate, resultSelector)).toBe(expected);
        expectSubscriptions(e1.subscriptions).toBe(e1subs);
    });
    it('should raise error when predicate throws', function () {
        var e1 = hot('--a--^---b---c---d---e--|');
        var e1subs = '^       !           ';
        var expected = '--------#           ';
        var predicate = function (x) {
            if (x === 'c') {
                throw 'error';
            }
            else {
                return false;
            }
        };
        expectObservable(e1.last(predicate)).toBe(expected);
        expectSubscriptions(e1.subscriptions).toBe(e1subs);
    });
    it('should raise error when result selector throws', function () {
        var e1 = hot('--a--^---b---c---d---e--|');
        var e1subs = '^       !           ';
        var expected = '--------#           ';
        var predicate = function (x) { return x === 'c'; };
        var resultSelector = function (x, i) {
            throw 'error';
        };
        expectObservable(e1.last(predicate, resultSelector)).toBe(expected);
        expectSubscriptions(e1.subscriptions).toBe(e1subs);
    });
});
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