Angular.js 将过滤器传递给指令双向 ('=') 属性 [英] Angular.js pass filter to directive bi-directional ('=') attribute

问题描述

我需要在页面的几个地方使用 sublist 指令，它有时应该包含完整的 fields 列表，但有时会被过滤.这是我天真的方法:

HTML:

 
<sublist fields="fields"/><!-- 这个没问题--><sublist fields="fields | filter: 'Rumba'"/><!-- 这个会引发错误-->

Javascript:

angular.module('myApp', []).directive('sublist', function () {返回 {限制:'E'，范围:{字段:'='}，模板:'<div ng-repeat="f in fields">{{f}}</div>'};}).controller('MainCtrl', function($scope) {$scope.fields = ['桑巴', '伦巴', '恰恰恰恰'];});

http://jsfiddle.net/GDfxd/14/

当我尝试使用过滤器时出现此错误:

错误:已达到 10 次 $digest() 迭代.中止！

这个问题有解决方案吗?

解决方案

$digest iterations 错误通常发生在观察者更改模型时.在错误情况下，隔离 fields 绑定绑定到过滤器的结果.该绑定创建了一个观察者.由于过滤器每次运行时都会从函数调用中返回一个新对象，因此它会导致观察者不断触发，因为旧值永远不会与新值匹配(参见 此评论来自 Google 网上论坛中的 Igor).

一个好的解决方法是在两种情况下绑定 fields，例如:

并为第二种情况添加另一个可选属性以进行过滤:

然后调整您的指令，如:

return {限制:'E'，范围: {字段:'='，过滤器:'='},模板:'<div ng-repeat="f in fields | filter:filterBy">'+'<small>我在这里:</small>{{f}}

'};

注意:记得关闭你的小提琴中的 sublist 标签.

这是一个小提琴

I need to use sublist directive in few places of the page, and it should contain sometimes full fields list, but sometimes filtered. Here is my naive approach:

HTML:

  <div ng-controller="MainCtrl">
      <sublist fields="fields" /> <!-- This one is OK -->
      <sublist fields="fields | filter: 'Rumba'" /> <!-- This one raises error -->
  </div>

Javascript:

angular.module('myApp', [])
    .directive('sublist', function () {
        return {
            restrict: 'E',
            scope: { fields: '=' },
            template: '<div ng-repeat="f in fields">{{f}}</div>'
        };
    })
    .controller('MainCtrl', function($scope) {
        $scope.fields = ['Samba', 'Rumba', 'Cha cha cha'];
    });

http://jsfiddle.net/GDfxd/14/

When I try to use filter I'm getting this error:

Error: 10 $digest() iterations reached. Aborting!

Is there a solution for this problem?

解决方案

The $digest iterations error typically happens when there is a watcher that changes the model. In the error case, the isolate fields binding is bound to the result of a filter. That binding creates a watcher. Since the filter returns a new object from a function invocation each time it runs, it causes the watcher to continually trigger, because the old value never matches the new (See this comment from Igor in Google Groups).

A good fix would be to bind fields in both cases like:

<sublist fields="fields" /></sublist>

And add another optional attribute to the second case for filtering:

<sublist fields="fields" filter-by="'Rumba'" /></sublist>

Then adjust your directive like:

return {
    restrict: 'E',
    scope: {
        fields: '=',
        filterBy: '='
    },
    template: '<div ng-repeat="f in fields | filter:filterBy">'+
              '<small>here i am:</small> {{f}}</div>'
};

Note: Remember to close your sublist tags in your fiddle.

Here is a fiddle

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