feat(facade): add equals method to StringMapWrapper

modules/angular2/src/facade/collection.dart

@@ -86,6 +86,17 @@ class StringMapWrapper {
     return a.keys.toList();
   }
   static bool isEmpty(Map m) => m.isEmpty;
+  static bool equals(Map m1, Map m2) {
+    if (m1.length != m2.length) {
+      return false;
+    }
+    for (var key in m1.keys) {
+      if (m1[key] != m2[key]) {
+        return false;
+      }
+    }
+    return true;
+  }
 }
 
 class ListWrapper {

modules/angular2/src/facade/collection.ts

@@ -86,6 +86,22 @@ export class StringMapWrapper {
 
     return m;
   }
+
+  static equals(m1, m2) {
+    var k1 = Object.keys(m1);
+    var k2 = Object.keys(m2);
+    if (k1.length != k2.length) {
+      return false;
+    }
+    var key;
+    for (var i = 0; i < k1.length; i++) {
+      key = k1[i];
+      if (m1[key] !== m2[key]) {
+        return false;
+      }
+    }
+    return true;
+  }
 }
 
 export class ListWrapper {

modules/angular2/test/facade/collection_spec.js

@@ -1,7 +1,7 @@
 import {describe, it, expect, beforeEach, ddescribe, iit, xit}
   from 'angular2/test_lib';
 
-import {List, ListWrapper} from 'angular2/src/facade/collection';
+import {List, ListWrapper, StringMap, StringMapWrapper} from 'angular2/src/facade/collection';
 
 export function main() {
   describe('ListWrapper', () => {
@@ -69,4 +69,44 @@ export function main() {
       });
     });
  });
+
+ describe('StringMapWrapper', () => {
+   describe('equals', () => {
+     it('should return true when comparing empty maps', () => {
+       expect(StringMapWrapper.equals({}, {})).toBe(true);
+     });
+
+     it('should return true when comparing the same map', () => {
+       var m1 = {'a': 1, 'b': 2, 'c': 3};
+       expect(StringMapWrapper.equals(m1, m1)).toBe(true);
+     });
+
+     it('should return true when comparing different maps with the same keys and values', () => {
+       var m1 = {'a': 1, 'b': 2, 'c': 3};
+       var m2 = {'a': 1, 'b': 2, 'c': 3};
+       expect(StringMapWrapper.equals(m1, m2)).toBe(true);
+     });
+
+     it('should return false when comparing maps with different numbers of keys', () => {
+       var m1 = {'a': 1, 'b': 2, 'c': 3};
+       var m2 = {'a': 1, 'b': 2, 'c': 3, 'd': 4};
+       expect(StringMapWrapper.equals(m1, m2)).toBe(false);
+       expect(StringMapWrapper.equals(m2, m1)).toBe(false);
+     });
+
+     it('should return false when comparing maps with different keys', () => {
+       var m1 = {'a': 1, 'b': 2, 'c': 3};
+       var m2 = {'a': 1, 'b': 2, 'CC': 3};
+       expect(StringMapWrapper.equals(m1, m2)).toBe(false);
+       expect(StringMapWrapper.equals(m2, m1)).toBe(false);
+     });
+
+     it('should return false when comparing maps with different values', () => {
+       var m1 = {'a': 1, 'b': 2, 'c': 3};
+       var m2 = {'a': 1, 'b': 20, 'c': 3};
+       expect(StringMapWrapper.equals(m1, m2)).toBe(false);
+       expect(StringMapWrapper.equals(m2, m1)).toBe(false);
+     });
+   });
+ });
 }