Add Array.prototype.includes

test/mjsunit/harmony/array-includes-to-object-strict.js

+// 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.
+
+// Flags: --harmony-array-includes
+
+// Ported from
+// https://github.com/tc39/Array.prototype.includes/blob/master/test/number-this.js
+// using https://www.npmjs.org/package/test262-to-mjsunit
+
+// Array.prototype.includes should use ToObject on this, so that when called
+// with a number, it picks up numeric properties from Number.prototype (even in
+// strict mode)
+(function() {
+  "use strict";
+
+  Number.prototype[0] = "a";
+  Number.prototype[1] = "b";
+
+  Object.defineProperty(Number.prototype, 2, {
+    get: function() {
+      assertEquals("object", typeof this);
+      return "c";
+    }
+  });
+
+  Number.prototype.length = 3;
+  assertTrue(Array.prototype.includes.call(5, "a"));
+  assertTrue(Array.prototype.includes.call(5, "b"));
+  assertTrue(Array.prototype.includes.call(5, "c"));
+  assertFalse(Array.prototype.includes.call(5, "d"));
+})();