extract Ember.isEmpty into ember-metal

Ember computed.empty should always have identical semantics

Author: stefanpenner

packages/ember-metal/lib/computed.js

@@ -437,7 +437,7 @@ Ember.computed.not = function(dependentKey) {
 Ember.computed.empty = function(dependentKey) {
   return Ember.computed(dependentKey, function(key) {
     var val = get(this, dependentKey);
-    return val === undefined || val === null || val === '' || (Ember.isArray(val) && get(val, 'length') === 0);
+    return Ember.isEmpty(val);
   });
 };
 

packages/ember-metal/lib/core.js

@@ -228,3 +228,30 @@ Ember.merge = function(original, updates) {
     original[prop] = updates[prop];
   }
 };
+/**
+  Verifies that a value is `null` or an empty string, empty array,
+  or empty function.
+
+  Constrains the rules on `Ember.isNone` by returning false for empty
+  string and empty arrays.
+
+  ```javascript
+  Ember.isEmpty();                // true
+  Ember.isEmpty(null);            // true
+  Ember.isEmpty(undefined);       // true
+  Ember.isEmpty('');              // true
+  Ember.isEmpty([]);              // true
+  Ember.isEmpty('Adam Hawkins');  // false
+  Ember.isEmpty([0,1,2]);         // false
+  ```
+
+  @method isEmpty
+  @for Ember
+  @param {Object} obj Value to test
+  @return {Boolean}
+*/
+Ember.isEmpty = function(obj) {
+  return obj === null || obj === undefined || (obj.length === 0 && typeof obj !== 'function') || (typeof obj === 'object' && Ember.get(obj, 'length') === 0);
+};
+Ember.empty = Ember.deprecateFunc("Ember.empty is deprecated. Please use Ember.isEmpty instead.", Ember.isEmpty) ;
+

packages/ember-runtime/tests/core/isEmpty_test.js renamed to packages/ember-metal/tests/core/is_empty_test.js

@@ -2,8 +2,7 @@ module("Ember.isEmpty");
 
 test("Ember.isEmpty", function() {
   var string = "string", fn = function() {},
-      object = {length: 0},
-      arrayProxy = Ember.ArrayProxy.create({ content: Ember.A([]) });
+      object = {length: 0};
 
   equal(true,  Ember.isEmpty(null),      "for null");
   equal(true,  Ember.isEmpty(undefined), "for undefined");
@@ -16,5 +15,4 @@ test("Ember.isEmpty", function() {
   equal(true,  Ember.isEmpty([]),        "for an empty Array");
   equal(false, Ember.isEmpty({}),        "for an empty Object");
   equal(true,  Ember.isEmpty(object),     "for an Object that has zero 'length'");
-  equal(true,  Ember.isEmpty(arrayProxy), "for an ArrayProxy that has empty content");
 });

packages/ember-runtime/lib/core.js

@@ -106,34 +106,6 @@ Ember.isNone = function(obj) {
 };
 Ember.none = Ember.deprecateFunc("Ember.none is deprecated. Please use Ember.isNone instead.", Ember.isNone);
 
-/**
-  Verifies that a value is `null` or an empty string, empty array,
-  or empty function.
-
-  Constrains the rules on `Ember.isNone` by returning false for empty
-  string and empty arrays.
-
-  ```javascript
-  Ember.isEmpty();                // true
-  Ember.isEmpty(null);            // true
-  Ember.isEmpty(undefined);       // true
-  Ember.isEmpty('');              // true
-  Ember.isEmpty([]);              // true
-  Ember.isEmpty('Adam Hawkins');  // false
-  Ember.isEmpty([0,1,2]);         // false
-  ```
-
-  @method isEmpty
-  @for Ember
-  @param {Object} obj Value to test
-  @return {Boolean}
-*/
-Ember.isEmpty = function(obj) {
-  return obj === null || obj === undefined || (obj.length === 0 && typeof obj !== 'function') || (typeof obj === 'object' && Ember.get(obj, 'length') === 0);
-};
-Ember.empty = Ember.deprecateFunc("Ember.empty is deprecated. Please use Ember.isEmpty instead.", Ember.isEmpty) ;
-
-/**
  This will compare two javascript values of possibly different types.
  It will tell you which one is greater than the other by returning:
 

packages/ember-runtime/tests/core/is_empty_test.js

@@ -0,0 +1,8 @@
+require('ember-metal/core');
+module("Ember.isEmpty");
+
+test("Ember.isEmpty", function() {
+  var arrayProxy = Ember.ArrayProxy.create({ content: Ember.A([]) });
+
+  equal(true,  Ember.isEmpty(arrayProxy), "for an ArrayProxy that has empty content");
+});