/* Any copyright is dedicated to the Public Domain. * http://creativecommons.org/licenses/publicdomain/ */ var sym = Symbol.for("moon"); function checkNotWritable(obj) { // In sloppy mode, assigning to a nonwritable property silently fails. obj[sym] = "portals"; assertEq(obj[sym], "cheese"); // In strict mode code, it throws. assertThrowsInstanceOf(function () { "use strict"; obj[sym] = "robots"; }, TypeError); assertEq(obj[sym], "cheese"); } var x = {}; Object.defineProperty(x, sym, { configurable: true, enumerable: true, value: "cheese", writable: false }); checkNotWritable(x); // Assignment can't shadow inherited nonwritable properties either. var y = Object.create(x); checkNotWritable(y); checkNotWritable(Object.create(y)); if (typeof reportCompare === "function") reportCompare(0, 0);