如果检查对象为空，作品有NG-节目而不是从控制？ [英] Checking if object is empty, works with ng-show but not from controller?

问题描述

我已经声明，像这样一个JS对象

I have a JS object declared like so

$scope.items = {};

我也有填充的项目该对象的$ HTTP请求。我想检测此项目是空的，看来NG-显示支持这个...我输入

I also have a $http request that fills this object with items. I would like to detect if this item is empty, it appears that ng-show supports this... I enter

ng-show="items"

和神奇它的作品，我也想从控制器做同样的，但我似乎无法得到它的工作，看来我可能不得不遍历对象看它是否有任何属性或使用lodash或下划线。

and magically it works,I would also like to do the same from a controller but i can't seem to get it to work, it appears I may have to iterate over the object to see if it has any properties or use lodash or underscore.

是否有其他选择吗？

我曾尝试

alert($scope.items == true);

但它始终返回false，当创建对象时 $ HTTP 填充，所以它不工作的方式。

but it always returns false , when the object is created and when populated with $http, so its not working that way.

推荐答案

使用一个空对象字面是没有必要在这里，你可以用null或undefined：

Use an empty object literal isn't necessary here, you can use null or undefined:

$scope.items = null;

在这种方式， NG-节目应继续工作，并在您的控制器你可以做：

In this way, ng-show should keep working, and in your controller you can just do:

if ($scope.items) {
    // items have value
} else {
    // items is still null
}

而在你的 $ HTTP 回调，你做到以下几点：

And in your $http callbacks, you do the following:

$http.get(..., function(data) {
    $scope.items = {
        data: data,
        // other stuff
    };
});

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