Implement String.prototype.codePointAt and String.fromCodePoint.

test/mjsunit/harmony/string-fromcodepoint.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-strings
+
+// Tests taken from:
+// https://github.com/mathiasbynens/String.fromCodePoint
+
+assertEquals(String.fromCodePoint.length, 1);
+assertEquals(String.propertyIsEnumerable("fromCodePoint"), false);
+
+assertEquals(String.fromCodePoint(""), "\0");
+assertEquals(String.fromCodePoint(), "");
+assertEquals(String.fromCodePoint(-0), "\0");
+assertEquals(String.fromCodePoint(0), "\0");
+assertEquals(String.fromCodePoint(0x1D306), "\uD834\uDF06");
+assertEquals(
+    String.fromCodePoint(0x1D306, 0x61, 0x1D307),
+    "\uD834\uDF06a\uD834\uDF07");
+assertEquals(String.fromCodePoint(0x61, 0x62, 0x1D307), "ab\uD834\uDF07");
+assertEquals(String.fromCodePoint(false), "\0");
+assertEquals(String.fromCodePoint(null), "\0");
+
+assertThrows(function() { String.fromCodePoint("_"); }, RangeError);
+assertThrows(function() { String.fromCodePoint("+Infinity"); }, RangeError);
+assertThrows(function() { String.fromCodePoint("-Infinity"); }, RangeError);
+assertThrows(function() { String.fromCodePoint(-1); }, RangeError);
+assertThrows(function() { String.fromCodePoint(0x10FFFF + 1); }, RangeError);
+assertThrows(function() { String.fromCodePoint(3.14); }, RangeError);
+assertThrows(function() { String.fromCodePoint(3e-2); }, RangeError);
+assertThrows(function() { String.fromCodePoint(-Infinity); }, RangeError);
+assertThrows(function() { String.fromCodePoint(+Infinity); }, RangeError);
+assertThrows(function() { String.fromCodePoint(NaN); }, RangeError);
+assertThrows(function() { String.fromCodePoint(undefined); }, RangeError);
+assertThrows(function() { String.fromCodePoint({}); }, RangeError);
+assertThrows(function() { String.fromCodePoint(/./); }, RangeError);
+assertThrows(function() { String.fromCodePoint({
+  valueOf: function() { throw Error(); } });
+}, Error);
+assertThrows(function() { String.fromCodePoint({
+  valueOf: function() { throw Error(); } });
+}, Error);
+var tmp = 0x60;
+assertEquals(String.fromCodePoint({
+  valueOf: function() { ++tmp; return tmp; }
+}), "a");
+assertEquals(tmp, 0x61);
+
+var counter = Math.pow(2, 15) * 3 / 2;
+var result = [];
+while (--counter >= 0) {
+  result.push(0); // one code unit per symbol
+}
+String.fromCodePoint.apply(null, result); // must not throw
+
+var counter = Math.pow(2, 15) * 3 / 2;
+var result = [];
+while (--counter >= 0) {
+  result.push(0xFFFF + 1); // two code units per symbol
+}
+String.fromCodePoint.apply(null, result); // must not throw