proxy-__proto__.js

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/*

 * Any copyright is dedicated to the Public Domain.

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

*/

var gTestfile = 'proxy-__proto__.js';

var BUGNUMBER = 950407;

var summary = "Behavior of __proto__ on ES6 proxies";

print(BUGNUMBER + ": " + summary);

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

 * BEGIN TEST *

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

var protoDesc = Object.getOwnPropertyDescriptor(Object.prototype, "__proto__");

var protoGetter = protoDesc.get;

var protoSetter = protoDesc.set;

function testProxy(target, initialProto)

  print("Now testing behavior for new Proxy(" + ("" + target) + ", {})");

  var pobj = new Proxy(target, {});

  // Check [[Prototype]] before attempted mutation

  assertEq(Object.getPrototypeOf(pobj), initialProto);

  assertEq(protoGetter.call(pobj), initialProto);

  // Attempt [[Prototype]] mutation

  protoSetter.call(pobj, null);

  // Check [[Prototype]] after attempted mutation

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

  assertEq(protoGetter.call(pobj), null);

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

// Proxy object with non-null [[Prototype]]

var nonNullProto = { toString: function() { return "non-null prototype"; } };

var target = Object.create(nonNullProto);

testProxy(target, nonNullProto);

// Proxy object with null [[Prototype]]

target = Object.create(null);

target.toString = function() { return "null prototype" };

testProxy(target, null);

// Proxy function with [[Call]]

var callForCallOnly = function () { };

callForCallOnly.toString = function() { return "callable target"; };

testProxy(callForCallOnly, Function.prototype);

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

if (typeof reportCompare === "function")

  reportCompare(true, true);

print("Tests complete");