AngularJS承诺返回空对象 [英] AngularJS promise returning empty object

问题描述

基本上我想要做的，就是从分配函数调用解析承诺一定借鉴价值。像这样

Basically what I want to do, is to assign some model value from function call that resolves promise. Like so

value = someFun()

这是我从中调用此功能的服务

This is a service from which I call this function

app.factory('SomeService', function($q) {
    return {
        someFun: function() {
            var d = $q.defer();
            try {
                d.resolve("hi");
            } catch (e) {
                d.reject(e);
            }
            return d.promise.then(function(text){
                return text;
            });
        }
    };
});

下面是HTML code

Here is the HTML code

<div ng-init="value = 'yes'">
    <pre>{{value |json}}</pre>
</div>
<button type="button" ng-click="value = someFun()">click me</button>

这是在控制器

$scope.someFun = SomeService.someFun;

下面是plnkr

http://plnkr.co/edit/qO5ofBXZDsi3cS3bBnT8

现在它返回一个空的对象。什么是错的？

Right now it returns an empty object. What is wrong?

编辑：正如下面已经回答了，是的，这是一种方式，但让我们说，我想打电话给SomeService.someFun在ngRepeat

As already answered below, yes this is one way, but let's say I want to call SomeService.someFun in ngRepeat?

EDIT2：下面是答案 - > <一个href=\"http://stackoverflow.com/questions/25329596/angular-ui-bootstrap-modal-inside-ngrepeat\">Angular里面ngRepeat

推荐答案

一般来说，如果你想使用的东西是异步更新出现在视图中，而无需编写控制器code，以及（这是在的情况下你的问题，你想叫NG-视图中的功能），那么你就需要返回一个空的占位符对象，无论是承诺的结果合并到它，或更新的对象，你可以在引用的属性视图。

Generally if you want to use something that is updated asynchronously to appear in a view without having to write controller code as well (which is the case in your question, as you wanted to call the function inside ng-view), then you need to return a blank placeholder object, and either merge the result of the promise into it, or update a property of that object which you can reference in the view.

您的问题是过于抽象知道处理这个有道理您的应用程序的具体方式，但这里是通用（和抽象的）想法的 plunker这里：

Your question is too abstract to know the exact way to approach this to make sense for your application, but here is the general (and abstracted) idea plunker here:

.factory('promiseService', function($q){
  return {
    someDeferredThing: function(){
      var placeholder = {};
      var d = $q.defer();
      d.promise.then(function(text){
        placeholder.text = text;
      });
      d.resolve("hi");
      return placeholder;
    }
  }
)

该服务将返回这是由承诺更新的对象，和不可以的承诺本身。如果返回一个承诺，那么你必须处理。然后（）等来获得的价值。

The service returns an object which is updated by the promise, and not a promise itself. If you return a promise then you have to deal with .then() etc. to get the value.

.controller('appCtrl', function($scope, promiseService){
  $scope.deferredResult = promiseService.someDeferredThing();
});

这是你如何分配值的范围。

This is how you assign the value to the scope.

$ scope.deferredResult.text 将不确定，直到承诺解决，那么这将成为定义和解决文字。因此，您的看法应该处理不确定状态一小段时间 - 通常这是非常简单的事，与 NG-节目

$scope.deferredResult.text will be undefined until the promise resolves, then it will become defined and resolve to "text". As such, your view should handle the undefined state for a short duration - usually it's very simple to do that with ng-show.

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