AngularJS 过滤器
过滤器可以使用一个管道字符（|）添加到表达式和指令中。
AngularJS中提供了如下几种过滤器：
| 过滤器 | 描述 |
|---|---|
| filter | 从数组项中选择一个子集 |
| currency | 格式化数字为货币格式 |
| number | 格式化数字为文本 |
| date | 格式化日期为指定格式字符串 |
| json | 允许将js对象转换为JSON字符串 |
| lowercase | 格式化字符串为小写 |
| uppercase | 格式化字符串为大写 |
| limitTo | 从数组或字符串项中选择制定长度的一个子集 |
| orderBy | 根据某个表达式排列数组 |
filter
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>AngularJS</title>
<script type="text/javascript" src="js/angular.min.js"></script>
<script type="text/javascript"> var app = angular.module("myApp", []); app.controller("myCtrl", function($scope) { $scope.items = []; for (var i = 0; i < 20; i++) { $scope.items.push("item" + i); } $scope.welcom = function() { return "Hello " + $scope.name; } }); </script>
</head>
<body ng-app="myApp" ng-controller="myCtrl">
<input type="text" ng-model="item" />
<ul>
<li ng-repeat="item in items|filter:item">{{item}}</li>
</ul>
</body>
</html>运行效果：
currency
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>AngularJS</title>
<script type="text/javascript" src="js/angular.min.js"></script>
<script type="text/javascript"> var app = angular.module("myApp", []); app.controller("myCtrl", function($scope) { $scope.amount = 100.25; }); </script>
</head>
<body ng-app="myApp" ng-controller="myCtrl">
<div>{{amount|currency}}</div>
<div>{{amount|currency:"￥"}}</div>
<div>{{amount|currency:"￥":1}}</div>
</body>
</html>运行效果：
number
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>AngularJS</title>
<script type="text/javascript" src="js/angular.min.js"></script>
<script type="text/javascript"> var app = angular.module("myApp", []); app.controller("myCtrl", function($scope) { $scope.amount = 100.25; }); </script>
</head>
<body ng-app="myApp" ng-controller="myCtrl">
<div>{{amount|number:1}}</div>
</body>
</html>运行效果：
date
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>AngularJS</title>
<script type="text/javascript" src="js/angular.min.js"></script>
<script type="text/javascript"> var app = angular.module("myApp", []); app.controller("myCtrl", function($scope) { $scope.now = new Date(); }); </script>
</head>
<body ng-app="myApp" ng-controller="myCtrl">
<div>{{now|date:'yyyy-MM-dd HH:mm:ss'}}</div>
</body>
</html>运行效果：
json
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>AngularJS</title>
<script type="text/javascript" src="js/angular.min.js"></script>
<script type="text/javascript"> var app = angular.module("myApp", []); app.controller("myCtrl", function($scope) { $scope.jsObj = { first: 'jiang', last: 'gujin' }; }); </script>
</head>
<body ng-app="myApp" ng-controller="myCtrl">
<div>{{jsObj|json}}</div>
</body>
</html>运行效果：
lowercase和uppercase
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>AngularJS</title>
<script type="text/javascript" src="js/angular.min.js"></script>
<script type="text/javascript"> var app = angular.module("myApp", []); app.controller("myCtrl", function($scope) { $scope.name = "jIanG guJiN"; }); </script>
</head>
<body ng-app="myApp" ng-controller="myCtrl">
<div>{{name|lowercase}}</div>
<div>{{name|uppercase}}</div>
</body>
</html>运行效果：
limitTo
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>AngularJS</title>
<script type="text/javascript" src="js/angular.min.js"></script>
<script type="text/javascript"> var app = angular.module("myApp", []); app.controller("myCtrl", function($scope) { $scope.name = "jiang gujin"; }); </script>
</head>
<body ng-app="myApp" ng-controller="myCtrl">
<div>{{name|limitTo:8}}</div>
</body>
</html>运行效果：
orderBy
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>AngularJS</title>
<script type="text/javascript" src="js/angular.min.js"></script>
<script type="text/javascript"> var app = angular.module("myApp", []); app.controller("myCtrl", function($scope) { $scope.friends = [{ name: 'John', phone: '555-1212', age: 10 }, { name: 'Mary', phone: '555-9876', age: 19 }, { name: 'Mike', phone: '555-4321', age: 21 }, { name: 'Adam', phone: '555-5678', age: 35 }, { name: 'Julie', phone: '555-8765', age: 29 }]; }); </script>
</head>
<body ng-app="myApp" ng-controller="myCtrl">
<table class="friend">
<tr>
<th><a href="" ng-click="predicate = 'name'; reverse=false">Name</a> (
<a href="" ng-click="predicate = '-name'; reverse=false">^</a>)</th>
<th><a href="" ng-click="predicate = 'phone'; reverse=!reverse">Phone Number</a></th>
<th><a href="" ng-click="predicate = 'age'; reverse=!reverse">Age</a></th>
</tr>
<tr ng-repeat="friend in friends | orderBy:predicate:reverse">
<td>{{friend.name}}</td>
<td>{{friend.phone}}</td>
<td>{{friend.age}}</td>
</tr>
</table>
</body>
</html>运行效果：
自定义过滤器
下面我们来实现一个字符串反转的过滤器。
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>AngularJS</title>
<script type="text/javascript" src="js/angular.min.js"></script>
<script type="text/javascript"> var app = angular.module("myApp", []); app.filter("reverse", function() { return function(input, uppercase) { var out = ""; for (var i = 0; i < input.length; i++) { out = input.charAt(i) + out; } if (uppercase) { out = out.toUpperCase(); } return out; } }); app.controller("myCtrl", function($scope) { $scope.name = "jianggujin"; }); </script>
</head>
<body ng-app="myApp" ng-controller="myCtrl">
<div>{{name|reverse}}</div>
<div>{{name|reverse:true}}</div>
</body>
</html>运行效果：