feat(ngModel): expose function to run model -> view pipeline

Closes angular#3407
Closes angular#10764

Author: Narretz

src/ng/directive/ngModel.js

@@ -878,6 +878,27 @@ NgModelController.prototype = {
    */
   $overrideModelOptions: function(options) {
     this.$options = this.$options.createChild(options);
+  },
+
+  $setModelValue: function(modelValue) {
+    this.$modelValue = this.$$rawModelValue = modelValue;
+    this.$$parserValid = undefined;
+
+    var formatters = this.$formatters,
+        idx = formatters.length;
+
+    var viewValue = modelValue;
+    while (idx--) {
+      viewValue = formatters[idx](viewValue);
+    }
+    if (this.$viewValue !== viewValue) {
+      this.$$updateEmptyClasses(viewValue);
+      this.$viewValue = this.$$lastCommittedViewValue = viewValue;
+      this.$render();
+
+      // It is possible that model and view value have been updated during render
+      this.$$runValidators(this.$modelValue, this.$viewValue, noop);
+    }
   }
 };
 
@@ -894,33 +915,15 @@ function setupModelWatcher(ctrl) {
     var modelValue = ctrl.$$ngModelGet(scope);
 
     // if scope model value and ngModel value are out of sync
-    // TODO(perf): why not move this to the action fn?
+    // This cannot be moved to the action function, because it would not catch the
+    // case where the model is changed in the ngChange function or the model setter
     if (modelValue !== ctrl.$modelValue &&
-       // checks for NaN is needed to allow setting the model to NaN when there's an asyncValidator
-        // eslint-disable-next-line no-self-compare
-       (ctrl.$modelValue === ctrl.$modelValue || modelValue === modelValue)
+      // checks for NaN is needed to allow setting the model to NaN when there's an asyncValidator
+      // eslint-disable-next-line no-self-compare
+     (ctrl.$modelValue === ctrl.$modelValue || modelValue === modelValue)
     ) {
-      ctrl.$modelValue = ctrl.$$rawModelValue = modelValue;
-      ctrl.$$parserValid = undefined;
-
-      var formatters = ctrl.$formatters,
-          idx = formatters.length;
-
-      var viewValue = modelValue;
-      while (idx--) {
-        viewValue = formatters[idx](viewValue);
-      }
-      if (ctrl.$viewValue !== viewValue) {
-        ctrl.$$updateEmptyClasses(viewValue);
-        ctrl.$viewValue = ctrl.$$lastCommittedViewValue = viewValue;
-        ctrl.$render();
-
-        // It is possible that model and view value have been updated during render
-        ctrl.$$runValidators(ctrl.$modelValue, ctrl.$viewValue, noop);
-      }
+      ctrl.$setModelValue(modelValue);
     }
-
-    return modelValue;
   });
 }
 

test/ng/directive/ngModelSpec.js

@@ -603,6 +603,59 @@ describe('ngModel', function() {
         expect(ctrl.$modelValue).toBeNaN();
 
       }));
+
+      describe('$setModelValue', function() {
+        it('should run the model -> view pipeline', function() {
+          var log = [];
+
+          ctrl.$formatters.unshift(function(value) {
+            log.push(value);
+            return value + 2;
+          });
+
+          ctrl.$formatters.unshift(function(value) {
+            log.push(value);
+            return value + '';
+          });
+
+          spyOn(ctrl, '$render');
+
+          ctrl.$setModelValue(3);
+
+          expect(ctrl.$modelValue).toBe(3);
+          expect(log).toEqual([3, 5]);
+          expect(ctrl.$viewValue).toBe('5');
+          expect(ctrl.$render).toHaveBeenCalledOnce();
+        });
+
+        it('should run the model -> view pipeline even if the value has not changed', function() {
+          // this is analogue to $setViewValue
+          spyOn(ctrl, '$render');
+
+          ctrl.$setModelValue(3);
+
+          expect(ctrl.$modelValue).toBe(3);
+          expect(ctrl.$render).toHaveBeenCalledOnce();
+
+          ctrl.$setModelValue(3);
+          expect(ctrl.$modelValue).toBe(3);
+          expect(ctrl.$render).toHaveBeenCalledOnce();
+        });
+
+        it('should not modify the scope value', function() {
+          // this is analogue to $setViewValue, which does not modify the rendered (DOM) value
+          scope.$apply('value = 10');
+          expect(ctrl.$modelValue).toBe(10);
+          expect(ctrl.$viewValue).toBe(10);
+
+          ctrl.$setModelValue(3);
+
+          expect(scope.value).toBe(10);
+          expect(ctrl.$modelValue).toBe(3);
+          expect(ctrl.$viewValue).toBe(3);
+        });
+
+      });
     });