Angularjs 角度-$手表上的$脏表不工作？

我试图观察使用Angular 1.x对表单的更改。我这样做是为了在用户在保存数据之前离开页面时显示警告。我可以$watchforform.$有效，很好，但form.$dirty永远不会开火。因此，明确地说，这是可行的：

$scope.$watch('forms.editForm.$valid', function (newVal, oldVal) {
    // This is how we tell if there are unsaved form changes so we don't navigate away
    $scope.unsavedFormChanges = oldVal;
}, true);

$scope.$watch('forms.editForm.$dirty', function (value) {
    // This is how we tell if there are unsaved form changes so we don't navigate away
    $scope.unsavedFormChanges = value;
    $log.info('Form Dirty Changed: ' + value);
}, false);

但这并不是：

$scope.$watch('forms.editForm.$dirty', function (newVal, oldVal) {
    // This is how we tell if there are unsaved form changes so we don't navigate away
    $scope.unsavedFormChanges = oldVal;
}, true);

---

有谁能告诉我为什么我不能观看$dirty，如果有备份计划的话谢谢

在我的头撞到墙上够久之后，我想我已经明白了这一点。似乎$valid是一个对象，$dirty是一个值。这就是第三个参数的作用。$watch语句末尾的“true”告诉$watch它正在看什么。True表示它是一个对象，False表示它是一个值。也就是说，这是可行的：

$scope.$watch('forms.editForm.$valid', function (newVal, oldVal) {
    // This is how we tell if there are unsaved form changes so we don't navigate away
    $scope.unsavedFormChanges = oldVal;
}, true);

$scope.$watch('forms.editForm.$dirty', function (value) {
    // This is how we tell if there are unsaved form changes so we don't navigate away
    $scope.unsavedFormChanges = value;
    $log.info('Form Dirty Changed: ' + value);
}, false);

---

我还将oldval/newval更改为一个值，因为这是我们得到的全部

在我的头撞到墙上足够长的时间后，我想我已经明白了这一点。似乎$valid是一个对象，$dirty是一个值。这就是第三个参数的作用。$watch语句末尾的“true”告诉$watch它正在看什么。True表示它是一个对象，False表示它是一个值。也就是说，这是可行的：

$scope.$watch('forms.editForm.$valid', function (newVal, oldVal) {
    // This is how we tell if there are unsaved form changes so we don't navigate away
    $scope.unsavedFormChanges = oldVal;
}, true);

$scope.$watch('forms.editForm.$dirty', function (value) {
    // This is how we tell if there are unsaved form changes so we don't navigate away
    $scope.unsavedFormChanges = value;
    $log.info('Form Dirty Changed: ' + value);
}, false);

我还将oldval/newval更改为一个值，因为这是我们得到的全部