construct-newtarget.js

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// |reftest| skip-if(!this.hasOwnProperty("Intl"))

/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

// Test subclassing %Intl.DateTimeFormat% works correctly.

class MyDateTimeFormat extends Intl.DateTimeFormat {}

var obj = new MyDateTimeFormat();

assertEq(obj instanceof MyDateTimeFormat, true);

assertEq(obj instanceof Intl.DateTimeFormat, true);

assertEq(Object.getPrototypeOf(obj), MyDateTimeFormat.prototype);

obj = Reflect.construct(MyDateTimeFormat, []);

assertEq(obj instanceof MyDateTimeFormat, true);

assertEq(obj instanceof Intl.DateTimeFormat, true);

assertEq(Object.getPrototypeOf(obj), MyDateTimeFormat.prototype);

obj = Reflect.construct(MyDateTimeFormat, [], MyDateTimeFormat);

assertEq(obj instanceof MyDateTimeFormat, true);

assertEq(obj instanceof Intl.DateTimeFormat, true);

assertEq(Object.getPrototypeOf(obj), MyDateTimeFormat.prototype);

obj = Reflect.construct(MyDateTimeFormat, [], Intl.DateTimeFormat);

assertEq(obj instanceof MyDateTimeFormat, false);

assertEq(obj instanceof Intl.DateTimeFormat, true);

assertEq(Object.getPrototypeOf(obj), Intl.DateTimeFormat.prototype);

// Set a different constructor as NewTarget.

obj = Reflect.construct(MyDateTimeFormat, [], Array);

assertEq(obj instanceof MyDateTimeFormat, false);

assertEq(obj instanceof Intl.DateTimeFormat, false);

assertEq(obj instanceof Array, true);

assertEq(Object.getPrototypeOf(obj), Array.prototype);

obj = Reflect.construct(Intl.DateTimeFormat, [], Array);

assertEq(obj instanceof Intl.DateTimeFormat, false);

assertEq(obj instanceof Array, true);

assertEq(Object.getPrototypeOf(obj), Array.prototype);

// The prototype defaults to %DateTimeFormatPrototype% if null.

function NewTargetNullPrototype() {}

NewTargetNullPrototype.prototype = null;

obj = Reflect.construct(Intl.DateTimeFormat, [], NewTargetNullPrototype);

assertEq(obj instanceof Intl.DateTimeFormat, true);

assertEq(Object.getPrototypeOf(obj), Intl.DateTimeFormat.prototype);

obj = Reflect.construct(MyDateTimeFormat, [], NewTargetNullPrototype);

assertEq(obj instanceof MyDateTimeFormat, false);

assertEq(obj instanceof Intl.DateTimeFormat, true);

assertEq(Object.getPrototypeOf(obj), Intl.DateTimeFormat.prototype);

// "prototype" property is retrieved exactly once.

var trapLog = [], getLog = [];

var ProxiedConstructor = new Proxy(Intl.DateTimeFormat, new Proxy({

    get(target, propertyKey, receiver) {

        getLog.push(propertyKey);

        return Reflect.get(target, propertyKey, receiver);

}, {

    get(target, propertyKey, receiver) {

        trapLog.push(propertyKey);

        return Reflect.get(target, propertyKey, receiver);

}));

obj = Reflect.construct(Intl.DateTimeFormat, [], ProxiedConstructor);

assertEqArray(trapLog, ["get"]);

assertEqArray(getLog, ["prototype"]);

assertEq(obj instanceof Intl.DateTimeFormat, true);

assertEq(Object.getPrototypeOf(obj), Intl.DateTimeFormat.prototype);

if (typeof reportCompare === "function")

    reportCompare(0, 0);