fromJson delegation to native JSON parser if available

- native parser delegation
- $xhr change to use native parser

perf/jsonPerfSpec.js

@@ -1,55 +1,28 @@
 describe('json', function() {
-  xit('should parse json in a reasonable time', function() {
-    var totalSubstr = 0,
-        totalGetMatch = 0,
-        totalConsume = 0,
-        totalTime = 0,
-        runTimes = [];
-    
-    for (var i=0; i<10; i++) {
-      window.substrTime = 0;
-      window.getMatchTime = 0;
-      window.consumeTime = 0;
-      var start = Date.now();
-      expect(angular.fromJson(largeJsonString)).toBeTruthy();
-      var time = Date.now() - start;
-//      dump('parse time', time, 'consume', window.consumeTime,
-//                               'substr', window.substrTime,
-//                               'getMatch', window.getMatchTime);
-      totalTime += time;
-      totalSubstr += window.substrTime;
-      totalGetMatch += window.getMatchTime;
-      totalConsume += window.consumeTime;
-      runTimes.push(time);
-    }
-
-    totalGetMatch = totalGetMatch - totalSubstr;
-
-    dump("totals", totalTime,
-          "| consume", totalConsume, '' + Math.round(totalConsume/(totalTime/100)) + '%',
-          "| substr", totalSubstr, '' + Math.round(totalSubstr/(totalTime/100)) + '%',
-          "| getMatch", totalGetMatch, '' + Math.round(totalGetMatch/(totalTime/100)) + '%');
-    dump("run times", runTimes);
-    delete window.consumeTime;
-    delete window.substrTime;
-    delete window.getMatchTime;
-  });
-
 
   it('angular parser', function() {
     var duration = time(function() {
       expect(angular.fromJson(largeJsonString)).toBeTruthy();
     }, 1);
 
-    expect(duration).toBeLessThan(4000);
+    dump(duration/1 + ' ms per iteration');
+  });
+
+
+  it('angular delegating to native parser', function() {
+    var duration = time(function() {
+      expect(angular.fromJson(largeJsonString, true)).toBeTruthy();
+    }, 100);
+
+    dump(duration/100 + ' ms per iteration');
   });
 
 
   it('native json', function() {
     var duration = time(function() {
       expect(JSON.parse(largeJsonString)).toBeTruthy();
-    }, 1);
+    }, 100);
 
-    expect(duration).toBeLessThan(200);
+    dump(duration/100 + ' ms per iteration');
   });
 });

src/Angular.js

@@ -109,7 +109,8 @@ var _undefined        = undefined,
     angularService    = extensionMap(angular, 'service'),
     angularCallbacks  = extensionMap(angular, 'callbacks'),
     nodeName,
-    rngScript         = /^(|.*\/)angular(-.*?)?(\.min)?.js(\?[^#]*)?(#(.*))?$/;
+    rngScript         = /^(|.*\/)angular(-.*?)?(\.min)?.js(\?[^#]*)?(#(.*))?$/,
+    DATE_ISOSTRING_LN = 24;
 
 /**
  * @workInProgress

src/JSON.js

@@ -29,19 +29,41 @@ function toJson(obj, pretty) {
  * Deserializes a string in the JSON format.
  *
  * @param {string} json JSON string to deserialize.
+ * @param {boolean} [useNative=false] Use native JSON parser if available
  * @returns {Object|Array|Date|string|number} Deserialized thingy.
  */
-function fromJson(json) {
+function fromJson(json, useNative) {
   if (!json) return json;
+
+  var obj, p, expression;
+
   try {
-    var p = parser(json, true);
-    var expression =  p.primary();
+    if (useNative && JSON && JSON.parse) {
+      obj = JSON.parse(json);
+      return transformDates(obj);
+    }
+
+    p = parser(json, true);
+    expression =  p.primary();
     p.assertAllConsumed();
     return expression();
+
   } catch (e) {
     error("fromJson error: ", json, e);
     throw e;
   }
+
+  // TODO make foreach optionally recursive and remove this function
+  function transformDates(obj) {
+    if (isString(obj) && obj.length === DATE_ISOSTRING_LN) {
+      return angularString.toDate(obj);
+    } else if (isArray(obj) || isObject(obj)) {
+      foreach(obj, function(val, name) {
+        obj[name] = transformDates(val);
+      });
+    }
+    return obj;
+  }
 }
 
 angular['toJson'] = toJson;

src/parser.js

@@ -26,7 +26,7 @@ var OPERATORS = {
 var ESCAPE = {"n":"\n", "f":"\f", "r":"\r", "t":"\t", "v":"\v", "'":"'", '"':'"'};
 
 function lex(text, parseStringsForObjects){
-  var dateParseLength = parseStringsForObjects ? 24 : -1,
+  var dateParseLength = parseStringsForObjects ? DATE_ISOSTRING_LN : -1,
       tokens = [],
       token,
       index = 0,

src/services.js

@@ -705,7 +705,7 @@ angularServiceInject('$xhr', function($browser, $error, $log){
     $browser.xhr(method, url, post, function(code, response){
       try {
         if (isString(response) && /^\s*[\[\{]/.exec(response) && /[\}\]]\s*$/.exec(response)) {
-          response = fromJson(response);
+          response = fromJson(response, true);
         }
         if (code == 200) {
           callback(code, response);

test/JsonSpec.js

@@ -116,6 +116,42 @@ describe('json', function(){
     expect(fromJson("{exp:1.2e-10}")).toEqual({exp:1.2E-10});
   });
 
+
+  //run these tests only in browsers that have native JSON parser
+  if (JSON && JSON.parse) {
+
+    describe('native parser', function() {
+
+      var nativeParser = JSON.parse;
+
+      afterEach(function() {
+        JSON.parse = nativeParser;
+      });
+
+
+      it('should delegate to native parser if available and boolean flag is passed', function() {
+        var spy = this.spyOn(JSON, 'parse').andCallThrough();
+
+        expect(fromJson('{}')).toEqual({});
+        expect(spy).wasNotCalled();
+
+        expect(fromJson('{}', true)).toEqual({});
+        expect(spy).wasCalled();
+      });
+
+
+      it('should convert timestamp strings to Date objects', function() {
+        expect(fromJson('"2010-12-22T17:23:17.974Z"', true) instanceof Date).toBe(true);
+        expect(fromJson('["2010-12-22T17:23:17.974Z"]', true)[0] instanceof Date).toBe(true);
+        expect(fromJson('{"t":"2010-12-22T17:23:17.974Z"}', true).t instanceof Date).toBe(true);
+        expect(fromJson('{"t":["2010-12-22T17:23:17.974Z"]}', true).t[0] instanceof Date).toBe(true);
+        expect(fromJson('{"t":{"t":"2010-12-22T17:23:17.974Z"}}', true).t.t instanceof Date).toBe(true);
+      });
+    });
+
+  }
+
+
   describe('security', function(){
     it('should not allow naked expressions', function(){
       expect(function(){fromJson('1+2');}).