如何看着AngularJS模式的变化，当我忽略了初始负荷？ [英] How do I ignore the initial load when watching model changes in AngularJS?

问题描述

我有一个网页，作为编辑为一个单一的实体，它位于如$ scope.fieldcontainer财产深刻的图表。之后，我从我的REST API（通过$资源）的响应，我的手表添加到FieldContainer中。我使用这款手表来检测，如果页面/实体是脏。现在我正在做保存按钮反弹，但我真的想打，直到用户弄脏模型保存按钮不可见的。

I have a web page that serves as the editor for a single entity, which sits as a deep graph in the $scope.fieldcontainer property. After I get a response from my REST API (via $resource), I add a watch to 'fieldcontainer'. I am using this watch to detect if the page/entity is "dirty". Right now I'm making the save button bounce but really I want to make the save button invisible until the user dirties the model.

我所得到的是手表，我认为正在发生的事情，因为.fieldcontainer = ...赋值发生后立即创建我的手表的一个触发。我想只使用一个dirtyCount属性来吸收初始误报但感觉非常哈克......我想通必须有一个角地道的方式来处理这个 - 我不是唯一的一个用手表来检测一个肮脏的典范。

What I am getting is a single trigger of the watch, which I think is happening because the .fieldcontainer = ... assignment takes place immediately after I create my watch. I was thinking of just using a "dirtyCount" property to absorb the initial false alarm but that feels very hacky ... and I figured there has to be an "Angular idiomatic" way to deal with this - I'm not the only one using a watch to detect a dirty model.

这里的code，我把手表：

Here's the code where I set my watch:

 $scope.fieldcontainer = Message.get({id: $scope.entityId },
            function(message,headers) {
                $scope.$watch('fieldcontainer',
                    function() {
                        console.log("model is dirty.");
                        if ($scope.visibility.saveButton) {
                            $('#saveMessageButtonRow').effect("bounce", { times:5, direction: 'right' }, 300);
                        }
                    }, true);
            });

我只是想起那里一定是要做到这一点比我守着UI弄脏code用更清洁的方式是如果（dirtyCount> 0）...

I just keep thinking there's got to be a cleaner way to do this than guarding my "UI dirtying" code with an "if (dirtyCount >0)"...

推荐答案

设置一个标志，只是在初始加载之前，

set a flag just before the initial load,

var initializing = true

，然后当第一$腕表火灾，做

and then when the first $watch fires, do

$scope.$watch('fieldcontainer', function() {
  if (initializing) {
    $timeout(function() { initializing = false; });
  } else {
    // do whatever you were going to do
  }
});

该标志将被推倒只是在目前的消化周期的结束，因此，接下来的改变不会被阻塞。

The flag will be tear down just at the end of the current digest cycle, so next change won't be blocked.

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