// Copyright 2014 the V8 project authors. All rights reserved. // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. // Note: concat does not currently support species so there is no difference // between [].concat(foo) and Array.prototype.concat.apply(foo). var getTrap = function(t, key) { if (key === "length") return {[Symbol.toPrimitive]() {return 3}}; if (key === "2") return "baz"; if (key === "3") return "bar"; }; var target = []; var obj = new Proxy(target, {get: getTrap, has: () => true}); assertEquals([undefined, undefined, "baz"], [].concat(obj)); assertEquals([undefined, undefined, "baz"], Array.prototype.concat.apply(obj))