[builtins] Refactor the remaining Date builtins.

src/js/json.js

 // Copyright 2009 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.
 
 (function(global, utils) {
 
 "use strict";
 
 %CheckIsBootstrapping();
 
 // -------------------------------------------------------------------
 // Imports
 
+var GlobalDate = global.Date;
 var GlobalJSON = global.JSON;
 var GlobalSet = global.Set;
 var InternalArray = utils.InternalArray;
 var MakeTypeError;
 var MaxSimple;
 var MinSimple;
 var ObjectHasOwnProperty;
 var toStringTagSymbol = utils.ImportNow("to_string_tag_symbol");
 
 utils.Import(function(from) {
@@ skipping 216 matching lines @@
 
 %AddNamedProperty(GlobalJSON, toStringTagSymbol, "JSON", READ_ONLY | DONT_ENUM);
 
 // Set up non-enumerable properties of the JSON object.
 utils.InstallFunctions(GlobalJSON, DONT_ENUM, [
   "parse", JSONParse,
   "stringify", JSONStringify
 ]);
 
 // -------------------------------------------------------------------
+// Date.toJSON
+
+// 20.3.4.37 Date.prototype.toJSON ( key )
+function DateToJSON(key) {
+  var o = TO_OBJECT(this);
+  var tv = TO_PRIMITIVE_NUMBER(o);
+  if (IS_NUMBER(tv) && !NUMBER_IS_FINITE(tv)) {
+    return null;
+  }
+  return o.toISOString();
+}
+
+// Set up non-enumerable functions of the Date prototype object.
+utils.InstallFunctions(GlobalDate.prototype, DONT_ENUM, [
+  "toJSON", DateToJSON
+]);
+
+// -------------------------------------------------------------------
 // JSON Builtins
 
 function JsonSerializeAdapter(key, object) {
   var holder = {};
   holder[key] = object;
   // No need to pass the actual holder since there is no replacer function.
   return JSONSerialize(key, holder, UNDEFINED, new InternalArray(), "", "");
 }
 
 %InstallToContext(["json_serialize_adapter", JsonSerializeAdapter]);
 
 })