使用AngularJS创建自定义的过滤器的方法

Angularjs过滤器是 angularjs非常棒的特性之一。有朝一日，你可能需要使用自定义过滤器，幸运的是，你找到了这篇博文。

下面显示的是自定义过滤器长什么样子(请注意myfilter):

我们的自定义过滤器叫做 "myfilter", 它有由 ':'隔开的4个参数.

这是一个将会用到的样本输入:

  $scope.friends = [{name:'John', phone:'555-1276'},
           {name:'Annie', phone:'800-BIG-MARY'},
           {name:'Mike', phone:'555-4321'},
           {name:'Adam', phone:'555-5678'},
           {name:'David', phone:'555-8765'},
           {name:'Mikay', phone:'555-5678'}];

过滤器只显示电话号码中含有 "555"的项，这是样本输出:

 Name   Phone
 John   555-1276
 Mike   555-4321
 Adam   555-5678
 David   555-8765
 Mikay   555-5678

过滤"555"的处理流程由 "windowScopedFilter"执行, 它是过滤器 'myfilter'的第四个参数.

下面我们来实现这些功能 (把logging添加到每个输入参数):

 var myapp = angular.module('MyFilterApp', []);
 myapp.filter('myfilter', function() {
  return function(input, param1) {
   console.log("------------------------------------------------- begin dump of custom parameters");
   console.log("input=",input);
   console.log("param1(string)=", param1);
   var args = Array.prototype.slice.call(arguments);
   console.log("arguments=", args.length);
   if (3<=args.length) {
      console.log("param2(string)=", args[2]);
   }
   if (4<=args.length) {
      console.log("param3(bool)=", args[3]);
   }
   console.log("------------------------------------------------- end dump of custom parameters");
   // filter
   if (5<=args.length) {
      return window[args[4]](input);
   }
   return input;
  };
 });

上面的代码大多都log了(译者注：将信息显示到控制台). 实际完成过滤的最重要的一部分是:

   // filter
   if (5<=args.length) {
      return window[args[4]](input);
   }
   return input;

"return window[args[4]](input)" 调用第四个参数, 它是 'windowScopedFilter'.

这是控制台输出:

 "------------------------------------------------- begin dump of custom parameters" custom_filter_function.html:21
 "input=" [object Array] custom_filter_function.html:22
 "param1(string)=" "param1" custom_filter_function.html:23
 "arguments=" 5 custom_filter_function.html:25
 "param2(string)=" "param2" custom_filter_function.html:27
 "param3(bool)=" true custom_filter_function.html:30
 "------------------------------------------------- end dump of custom parameters" custom_filter_function.html:32
 "------------------------------------------------- begin dump of custom parameters" custom_filter_function.html:21
 "input=" [object Array] custom_filter_function.html:22
 "param1(string)=" "param1" custom_filter_function.html:23
 "arguments=" 5 custom_filter_function.html:25
 "param2(string)=" "param2" custom_filter_function.html:27
 "param3(bool)=" true custom_filter_function.html:30
 "------------------------------------------------- end dump of custom parameters" custom_filter_function.html:32

完整代码:

<html>
 <head>
 <script src="angular.min.js"></script>
 <script type="text/javascript">
 function windowScopedFilter (input) {
   var output = [];
   angular.forEach(input, function(v,k){
      if (v.phone.contains("555")) {
        output.push(v);
      }
   });
   return output;
 }
 var myapp = angular.module('MyFilterApp', []);
 myapp.filter('myfilter', function() {
  return function(input, param1) {
   console.log("------------------------------------------------- begin dump of custom parameters");
   console.log("input=",input);
   console.log("param1(string)=", param1);
   var args = Array.prototype.slice.call(arguments);
   console.log("arguments=", args.length);
   if (3<=args.length) {
      console.log("param2(string)=", args[2]);
   }
   if (4<=args.length) {
      console.log("param3(bool)=", args[3]);
   }
   console.log("------------------------------------------------- end dump of custom parameters");
   // filter
   if (5<=args.length) {
      return window[args[4]](input);
   }
   return input;
  };
 });
 myapp.controller('MyFilterController', ['$scope', function($scope) {
  $scope.friends = [{name:'John', phone:'555-1276'},
           {name:'Annie', phone:'800-BIG-MARY'},
           {name:'Mike', phone:'555-4321'},
           {name:'Adam', phone:'555-5678'},
           {name:'David', phone:'555-8765'},
           {name:'Mikay', phone:'555-5678'}];
 }]);
 </script>
 </head>
 <body ng-app="MyFilterApp">
 <div ng-controller="MyFilterController">
   <table id="searchTextResults">
    <tr><th>Name</th><th>Phone</th></tr>
    <tr ng-repeat="friend in friends |myfilter:'param1':'param2':true:'windowScopedFilter'">
    <td>{{friend.name}}</td>
    <td>{{friend.phone}}</td>
    </tr>
   </table>
 </div>
 <hr>
 </body>
 </html>