48 lines
1.4 KiB
JavaScript
48 lines
1.4 KiB
JavaScript
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/* global it, describe, assert, Promise */
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describe('Support user subclassing of Promise', function () {
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'use strict';
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it('should work if you do it right', function (done) {
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// This is the "correct" es6-compatible way.
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// (Thanks, @domenic and @zloirock!)
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var MyPromise = function (executor) {
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var self = new Promise(executor);
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Object.setPrototypeOf(self, MyPromise.prototype);
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self.mine = 'yeah';
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return self;
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};
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if (!Object.setPrototypeOf) { return done(); } // skip test if on IE < 11
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Object.setPrototypeOf(MyPromise, Promise);
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MyPromise.prototype = Object.create(Promise.prototype, {
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constructor: { value: MyPromise }
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});
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// let's try it!
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var p1 = MyPromise.resolve(5);
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assert.strictEqual(p1.mine, 'yeah');
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p1 = p1.then(function (x) {
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assert.strictEqual(x, 5);
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});
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assert.strictEqual(p1.mine, 'yeah');
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var p2 = new MyPromise(function (r) { r(6); });
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assert.strictEqual(p2.mine, 'yeah');
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p2 = p2.then(function (x) {
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assert.strictEqual(x, 6);
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});
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assert.strictEqual(p2.mine, 'yeah');
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var p3 = MyPromise.all([p1, p2]);
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assert.strictEqual(p3.mine, 'yeah');
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p3.then(function () { done(); }, done);
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});
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it("should throw if you don't inherit at all", function () {
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var MyPromise = function () {};
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assert['throws'](function () {
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Promise.all.call(MyPromise, []);
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}, TypeError);
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});
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});
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