// Map methods throw when passed a this-value that isn't a Map. load(libdir + "asserts.js"); function testcase(obj, fn, ...args) { assertEq(typeof fn, "function"); assertThrowsInstanceOf(function () { fn.apply(obj, args); }, TypeError); } var Map_size_getter = Object.getOwnPropertyDescriptor(Map.prototype, "size").get; function test(obj) { testcase(obj, Map.prototype.get, "x"); testcase(obj, Map.prototype.has, "x"); testcase(obj, Map.prototype.set, "x", 1); testcase(obj, Map.prototype.delete, "x"); testcase(obj, Map.prototype.clear); testcase(obj, Map.prototype.keys); testcase(obj, Map.prototype.values); testcase(obj, Map.prototype.entries); testcase(obj, Map_size_getter); } test(Map.prototype); test(Object.create(new Map)); test(new Set()); test({}); test(null); test(undefined);