JSTests/test262/test/built-ins/Map/prototype/size/does-not-have-mapdata-internal-slot.js

// Copyright (C) 2015 the V8 project authors. All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.
/*---
es6id: 23.1.3.9
description: >
  Throws a TypeError if `this` object does not have a [[MapData]] internal slot.
info: |
  get Map.prototype.size

  1. Let M be the this value.
  2. If Type(M) is not Object, throw a TypeError exception.
  3. If M does not have a [[MapData]] internal slot, throw a TypeError
  exception.
  ...
---*/

var descriptor = Object.getOwnPropertyDescriptor(Map.prototype, 'size');

var map = new Map();

// Does not throw
descriptor.get.call(map);

assert.throws(TypeError, function() {
  descriptor.get.call([]);
});