weakRefs-basic.js - mozsearch

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assertEq('WeakRef' in this, true);

function checkPropertyDescriptor(obj, property, writable, enumerable,

                                 configurable) {

  let desc = Object.getOwnPropertyDescriptor(obj, property);

  assertEq(typeof desc, "object");

  assertEq(desc.writable, writable);

  assertEq(desc.enumerable, enumerable);

  assertEq(desc.configurable, configurable);

function assertThrowsTypeError(thunk) {

  let error;

  try {

      thunk();

  } catch (e) {

      error = e;

  assertEq(error instanceof TypeError, true);

assertEq(typeof this.WeakRef, "function");

// https://tc39.es/proposal-weakrefs/

// 1.1.1.1

// If NewTarget is undefined, throw a TypeError exception.

assertThrowsTypeError(() => new WeakRef());

// 1.1.1.2

// If Type(target) is not Object, throw a TypeError exception.

assertThrowsTypeError(() => new WeakRef(1));

assertThrowsTypeError(() => new WeakRef(true));

assertThrowsTypeError(() => new WeakRef("string"));

assertThrowsTypeError(() => new WeakRef(Symbol()));

assertThrowsTypeError(() => new WeakRef(null));

assertThrowsTypeError(() => new WeakRef(undefined));

new WeakRef({});

// 1.2

// The WeakRef constructor has a [[Prototype]] internal slot whose value is the

// intrinsic object %FunctionPrototype%.

assertEq(Object.getPrototypeOf(WeakRef), Function.prototype);

// 1.2.1

// The initial value of WeakRef.prototype is the intrinsic %WeakRefPrototype%

// object.

// This property has the attributes { [[Writable]]: false, [[Enumerable]]: false

// , [[Configurable]]: false }.

checkPropertyDescriptor(WeakRef, 'prototype', false, false, false);

// 1.3

// The WeakRef prototype object has a [[Prototype]] internal slot whose value is

// the intrinsic object %ObjectPrototype%.

let proto = WeakRef.prototype;

assertEq(Object.getPrototypeOf(proto), Object.prototype);

// 1.3.1

// The initial value of WeakRef.prototype.constructor is the intrinsic object

// %WeakRef%.

assertEq(proto.constructor, WeakRef);

// 1.3.2

// WeakRef.prototype.deref ()

assertEq(proto.hasOwnProperty('deref'), true);

assertEq(typeof proto.deref, 'function');

// 1.3.3

// The initial value of the @@toStringTag property is the String value

// "WeakRef".

// This property has the attributes { [[Writable]]: false, [[Enumerable]]: false,

// [[Configurable]]: true }.

assertEq(proto[Symbol.toStringTag], "WeakRef");

checkPropertyDescriptor(proto, Symbol.toStringTag, false, false, true);

// 1.4

// WeakRef instances are ordinary objects that inherit properties from the

// WeakRef prototype

let weakRef = new WeakRef({});

assertEq(Object.getPrototypeOf(weakRef), proto);