Add Object.isDate. [#443 state:resolved] (Nesterenko Dmitry, kangax, …

…Samuel Lebeau, Andrew Dupont)
juzna · Oct 17, 2010 · 05e0ebc · 05e0ebc
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diff --git a/CHANGELOG b/CHANGELOG
@@ -1,3 +1,5 @@
+* Add Object.isDate. [#443 state:resolved] (Nesterenko Dmitry, kangax, Samuel Lebeau, Andrew Dupont)
+
 * Handle cases where `document` or `document.documentElement` is passed into Element#getOffsetParent. Fixes IE errors with many layout/positioning methods. [#90 state:resolved] (Padraig Kennedy, Andrew Dupont)
 
 * Wrap `element` in `$` for Element#cumulativeOffset, #viewportOffset, #positionedOffset, and #getOffsetParent. [#782 state:resolved] (Radoslav Stankov, Andrew Dupont)

diff --git a/src/lang/object.js b/src/lang/object.js
@@ -32,6 +32,7 @@
       NUMBER_CLASS = '[object Number]',
       STRING_CLASS = '[object String]',
       ARRAY_CLASS = '[object Array]',
+      DATE_CLASS = '[object Date]',
       NATIVE_JSON_STRINGIFY_SUPPORT = window.JSON &&
         typeof JSON.stringify === 'function' &&
         JSON.stringify(0) === '0' &&
@@ -513,6 +514,27 @@
   function isNumber(object) {
     return _toString.call(object) === NUMBER_CLASS;
   }
+
+  /**
+   *  Object.isDate(object) -> Boolean
+   *  - object (Object): The object to test.
+   *  
+   *  Returns `true` if `object` is of type [[Date]]; `false` otherwise.
+   *  
+   *  ##### Examples
+   *  
+   *      Object.isDate(new Date);
+   *      //-> true
+   *  
+   *      Object.isDate("Dec 25, 1995");
+   *      //-> false
+   *  
+   *      Object.isDate(new Date("Dec 25, 1995"));
+   *      //-> true
+  **/
+  function isDate(object) {
+    return _toString.call(object) === DATE_CLASS;
+  }
 
   /**
    *  Object.isUndefined(object) -> Boolean
@@ -556,6 +578,7 @@
     isFunction:    isFunction,
     isString:      isString,
     isNumber:      isNumber,
+    isDate:        isDate,
     isUndefined:   isUndefined
   });
 })();
diff --git a/test/unit/object_test.js b/test/unit/object_test.js
@@ -160,6 +160,25 @@ new Test.Unit.Runner({
     this.assert(!Object.isNumber(undefined));
     this.assert(!Object.isNumber(document), 'host objects should return false rather than throw exceptions');
   },
+
+  testObjectIsDate: function() {
+    var d = new Date();
+    this.assert(Object.isDate(d), 'constructor with no arguments');
+    this.assert(Object.isDate(new Date(0)), 'constructor with milliseconds');
+    this.assert(Object.isDate(new Date(1995, 11, 17)), 'constructor with Y, M, D');
+    this.assert(Object.isDate(new Date(1995, 11, 17, 3, 24, 0)), 'constructor with Y, M, D, H, M, S');
+    this.assert(Object.isDate(new Date(Date.parse("Dec 25, 1995"))), 'constructor with result of Date.parse');
+
+    this.assert(!Object.isDate(d.valueOf()), 'Date#valueOf returns a number');
+    this.assert(!Object.isDate(function() { }));
+    this.assert(!Object.isDate(0));
+    this.assert(!Object.isDate("a string"));
+    this.assert(!Object.isDate([]));
+    this.assert(!Object.isDate({}));
+    this.assert(!Object.isDate(false));
+    this.assert(!Object.isDate(undefined));
+    this.assert(!Object.isDate(document), 'host objects should return false rather than throw exceptions');
+  },
 
   testObjectIsUndefined: function() {
     this.assert(Object.isUndefined(undefined));