feat($compile): add one-way collection bindings

src/ng/compile.js

@@ -339,6 +339,11 @@
  *   One-way binding is useful if you do not plan to propagate changes to your isolated scope bindings
  *   back to the parent. However, it does not make this completely impossible.
  *
+ *   By default, the {@link ng.$rootScope.Scope#$watch `$watch`}
+ *   method is used for tracking changes, and the equality check is based on object identity.
+ *   It's also possible to watch the evaluated value shallowly with
+ *   {@link ng.$rootScope.Scope#$watchCollection `$watchCollection`}: use `<*` or `<*attr`
+ *
  * * `&` or `&attr` - provides a way to execute an expression in the context of the parent scope. If
  *   no `attr` name is specified then the attribute name is assumed to be the same as the local name.
  *   Given `<my-component my-attr="count = count + value">` and the isolate scope definition `scope: {
@@ -1068,7 +1073,7 @@ function $CompileProvider($provide, $$sanitizeUriProvider) {
   var bindingCache = createMap();
 
   function parseIsolateBindings(scope, directiveName, isController) {
-    var LOCAL_REGEXP = /^([@&<]|=(\*?))(\??)\s*([\w$]*)$/;
+    var LOCAL_REGEXP = /^([@&]|[=<](\*?))(\??)\s*([\w$]*)$/;
 
     var bindings = createMap();
 
@@ -3626,7 +3631,7 @@ function $CompileProvider($provide, $$sanitizeUriProvider) {
             var initialValue = destination[scopeName] = parentGet(scope);
             initialChanges[scopeName] = new SimpleChange(_UNINITIALIZED_VALUE, destination[scopeName]);
 
-            removeWatch = scope.$watch(parentGet, function parentValueWatchAction(newValue, oldValue) {
+            removeWatch = scope[definition.collection ? '$watchCollection' : '$watch'](parentGet, function parentValueWatchAction(newValue, oldValue) {
               if (oldValue === newValue) {
                 if (oldValue === initialValue || (isLiteral && equals(oldValue, initialValue))) {
                   return;

test/ng/compileSpec.js

@@ -5148,6 +5148,9 @@ describe('$compile', function() {
             owOptref: '<?',
             owOptrefAlias: '<? owOptref',
             $owOptrefAlias: '<? $owOptref$',
+            owColref: '<*',
+            owColrefAlias: '<* owColref',
+            $owColrefAlias: '<* $owColref$',
             expr: '&',
             optExpr: '&?',
             exprAlias: '&expr',
@@ -6327,6 +6330,112 @@ describe('$compile', function() {
       });
     });
 
+    describe('one-way collection bindings', function() {
+      it('should update isolate scope when origin scope changes', inject(function() {
+        $rootScope.collection = [{
+          name: 'Gabriel',
+          value: 18
+        }, {
+          name: 'Tony',
+          value: 91
+        }];
+        $rootScope.query = '';
+        $rootScope.$apply();
+
+        compile('<div><span my-component ow-colref="collection | filter:query" $ow-colref$="collection | filter:query">');
+
+        expect(componentScope.owColref).toEqual($rootScope.collection);
+        expect(componentScope.owColrefAlias).toEqual(componentScope.owColref);
+        expect(componentScope.$owColrefAlias).toEqual(componentScope.owColref);
+
+        $rootScope.query = 'Gab';
+        $rootScope.$apply();
+
+        expect(componentScope.owColref).toEqual([$rootScope.collection[0]]);
+        expect(componentScope.owColrefAlias).toEqual([$rootScope.collection[0]]);
+        expect(componentScope.$owColrefAlias).toEqual([$rootScope.collection[0]]);
+      }));
+
+      it('should not update isolate scope when deep state within origin scope changes', inject(function() {
+        $rootScope.collection = [{
+          name: 'Gabriel',
+          value: 18
+        }, {
+          name: 'Tony',
+          value: 91
+        }];
+        $rootScope.$apply();
+
+        compile('<div><span my-component ow-colref="collection" $ow-colref$="collection">');
+
+        expect(componentScope.owColref).toEqual($rootScope.collection);
+        expect(componentScope.owColrefAlias).toEqual(componentScope.owColref);
+        expect(componentScope.$owColrefAlias).toEqual(componentScope.owColref);
+
+        componentScope.owColref = componentScope.owColrefAlias = componentScope.$owColrefAlias = undefined;
+        $rootScope.collection[0].name = 'Joe';
+        $rootScope.$apply();
+
+        expect(componentScope.owColref).toBeUndefined();
+        expect(componentScope.owColrefAlias).toBeUndefined();
+        expect(componentScope.$owColrefAlias).toBeUndefined();
+      }));
+
+      it('should update isolate scope when origin scope changes', inject(function() {
+        $rootScope.gab = {
+          name: 'Gabriel',
+          value: 18
+        };
+        $rootScope.tony = {
+          name: 'Tony',
+          value: 91
+        };
+        $rootScope.query = '';
+        $rootScope.$apply();
+
+        compile('<div><span my-component ow-colref="[gab, tony] | filter:query" $ow-colref$="[gab, tony] | filter:query">');
+
+        expect(componentScope.owColref).toEqual([$rootScope.gab, $rootScope.tony]);
+        expect(componentScope.owColrefAlias).toEqual([$rootScope.gab, $rootScope.tony]);
+        expect(componentScope.$owColrefAlias).toEqual([$rootScope.gab, $rootScope.tony]);
+
+        $rootScope.query = 'Gab';
+        $rootScope.$apply();
+
+        expect(componentScope.owColref).toEqual([$rootScope.gab]);
+        expect(componentScope.owColrefAlias).toEqual([$rootScope.gab]);
+        expect(componentScope.$owColrefAlias).toEqual([$rootScope.gab]);
+      }));
+
+      it('should update isolate scope when origin literal object content changes', inject(function() {
+        $rootScope.gab = {
+          name: 'Gabriel',
+          value: 18
+        };
+        $rootScope.tony = {
+          name: 'Tony',
+          value: 91
+        };
+        $rootScope.$apply();
+
+        compile('<div><span my-component ow-colref="[gab, tony]" $ow-colref$="[gab, tony]">');
+
+        expect(componentScope.owColref).toEqual([$rootScope.gab, $rootScope.tony]);
+        expect(componentScope.owColrefAlias).toEqual([$rootScope.gab, $rootScope.tony]);
+        expect(componentScope.$owColrefAlias).toEqual([$rootScope.gab, $rootScope.tony]);
+
+        $rootScope.tony = {
+          name: 'Bob',
+          value: 42
+        };
+        $rootScope.$apply();
+
+        expect(componentScope.owColref).toEqual([$rootScope.gab, $rootScope.tony]);
+        expect(componentScope.owColrefAlias).toEqual([$rootScope.gab, $rootScope.tony]);
+        expect(componentScope.$owColrefAlias).toEqual([$rootScope.gab, $rootScope.tony]);
+      }));
+    });
+
     describe('executable expression', function() {
       it('should allow expression execution with locals', inject(function() {
         compile('<div><span my-component expr="count = count + offset" $expr$="count = count + offset">');