trap-null.js - mozsearch

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/*

 * Any copyright is dedicated to the Public Domain.

 * http://creativecommons.org/licenses/publicdomain/

*/

var gTestfile = 'trap-null.js';

var BUGNUMBER = 1257102;

var summary = "null as a trap value on a handler should operate on the target";

print(BUGNUMBER + ": " + summary);

/**************

 * BEGIN TEST *

 **************/

// This might seem like overkill, but this proxying trick caught typos of

// several trap names before this test landed.  \o/  /o\

var allTraps = {

  getPrototypeOf: null,

  setPrototypeOf: null,

  isExtensible: null,

  preventExtensions: null,

  getOwnPropertyDescriptor: null,

  defineProperty: null,

  has: null,

  get: null,

  set: null,

  deleteProperty: null,

  ownKeys: null,

  apply: null,

  construct: null,

};

var complainingHandler = new Proxy(allTraps, {

  get(target, p, receiver) {

    var v = Reflect.get(target, p, receiver);

    if (v !== null)

      throw new TypeError("failed to set one of the traps to null?  " + p);

    return v;

});

var proxyTarget = function(x) {

  "use strict";

  var str = this + x;

  str += new.target ? "constructing" : "calling";

  return new.target ? new String(str) : str;

};

proxyTarget.prototype.toString = () => "###";

proxyTarget.prototype.valueOf = () => "@@@";

var proxy = new Proxy(proxyTarget, complainingHandler);

assertEq(Reflect.getPrototypeOf(proxy), Function.prototype);

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

assertEq(Reflect.setPrototypeOf(proxy, null), true);

assertEq(Object.getPrototypeOf(proxyTarget), null);

assertEq(Reflect.isExtensible(proxy), true);

assertEq(Reflect.isExtensible(proxyTarget), true);

assertEq(Reflect.preventExtensions(proxy), true);

assertEq(Reflect.isExtensible(proxy), false);

assertEq(Reflect.isExtensible(proxyTarget), false);

var desc = Reflect.getOwnPropertyDescriptor(proxy, "length");

assertEq(desc.value, 1);

assertEq(desc.configurable, true);

assertEq(Reflect.defineProperty(proxy, "length", { value: 3, configurable: false }), true);

desc = Reflect.getOwnPropertyDescriptor(proxy, "length");

assertEq(desc.configurable, false);

assertEq(Reflect.has(proxy, "length"), true);

assertEq(Reflect.get(proxy, "length"), 3);

assertEq(Reflect.set(proxy, "length", 3), false);

assertEq(Reflect.deleteProperty(proxy, "length"), false);

var keys = Reflect.ownKeys(proxy);

assertEq(keys.length, 3);

keys.sort();

assertEq(keys[0], "length");

assertEq(keys[1], "name");

assertEq(keys[2], "prototype");

assertEq(Reflect.apply(proxy, "hi!", [" "]), "hi! calling");

var res = Reflect.construct(proxy, [" - "]);

assertEq(typeof res, "object");

assertEq(res instanceof String, true);

assertEq(res.valueOf(), "@@@ - constructing");

/******************************************************************************/

if (typeof reportCompare === "function")

  reportCompare(true, true);

print("Tests complete");