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AngularJS 霸道的过滤器小结

时间：2021-05-03 10:00:39|栏目：AngularJS|点击： 次

一、为什么使用过滤器？

在实际操作中，我们需要对统一数据源进行多次转换，比如我的货币单位，在不同的国家我们将用不同的符号表示。因此，你可能会想到在控制器中判断国家以显示不同的结果，但是过滤器却可以更好的帮助我们做到同样的效果。

过滤器将数据在被指令处理并显示到视图之前进行转换，而不必修改作用域中原有的数据，这样能够允许同一份数据在应用中的不同部分以不同形式得以展示。

接下来，我们详细讨论有关过滤器的用法

二、过滤单个数据的值

下表展示用于单个数据的内置过滤器

这里写图片描述 

先来看看我们的准备案例，待会我们将在这个案例的基础上来使用内容过滤器

<!DOCTYPE>
<!-- use module -->
<html ng-app="exampleApp">
<head>
  <title>Angluar test</title>
  <meta charset="utf-8"/>
  <link rel="stylesheet" type="text/css" href="css/bootstrap.min.css" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >
  <link rel="stylesheet" type="text/css" href="css/bootstrap-theme.min.css" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >
</head>
<body>
  <dlv class="panel panel-default" ng-controller="defaultCtrl">
    <div class="panel panel-header">
      Products
      <span class="label label-primary">{{products.length}}</span>
    </div>
    <div class="panel panel-body">
      <table class="table table-striped table-bordered table-hover">
        <thead>
          <tr><th>Name</th><th>Category</th><th>Expiry</th><th>Price</th></tr>
        </thead>
        <tbody>
          <tr ng-repeat="p in products">
            <td>{{p.name}}</td>
            <td>{{p.category}}</td>
            <td>{{p.expiry}}</td>
            <td>{{p.price}}</td>
          </tr>
        </tbody>
      </table>
    </div>
  </dlv>

<script type="text/javascript" src="js/angular.min.js"></script>
<script type="text/javascript">
var myApp = angular.module("exampleApp", []);
myApp.controller("defaultCtrl", function ($scope) {
  $scope.products = [
    { name: "Apples", category: "Fruit", price: 1.20, expiry: 10 },
    { name: "Bananas", category: "Fruit", price: 2.42, expiry: 7 },
    { name: "Pears", category: "Fruit", price: 2.02, expiry: 6 },
    { name: "Tuna", category: "Fish", price: 20.45, expiry: 3 },
    { name: "Salmon", category: "Fish", price: 17.93, expiry: 2 },
    { name: "Trout", category: "Fish", price: 12.93, expiry: 4 },
    { name: "Beer", category: "Drinks", price: 2.99, expiry: 365 },
    { name: "Wine", category: "Drinks", price: 8.99, expiry: 365 },
    { name: "Whiskey", category: "Drinks", price: 45.99, expiry: 365 }
  ];
})
</script>
</body>
</html>

就是一个表格的形式来展示产品的详细情况的案例

这里写图片描述

1.格式化货币值

<tr ng-repeat="p in products">
  <td>{{p.name}}</td>
  <td>{{p.category}}</td>
  <td>{{p.expiry}}</td>
  <!-- 使用currency -->
  <td>{{p.price | currency}}</td>
</tr>

这里写图片描述

2.格式化数字值

<tr ng-repeat="p in products">
  <td>{{p.name}}</td>
  <td>{{p.category}}</td>
  <td>{{p.expiry}}</td>
  <!-- 保留小数点后3位 -->
  <td>{{p.price | number : 3}}</td>
</tr>

这里写图片描述

3.格式化日期

// 在控制器中添加
$scope.getExpiryDate = function (days) {
  var now = new Date();
  return now.setDate(now.getDate() + days);
}
<tr ng-repeat="p in products">
  <td>{{p.name}}</td>
  <td>{{p.category}}</td>
  <!-- 在视图中使用-->
  <td>{{getExpiryDate(p.expiry) | date : 'yyyy/MM/dd'}}</td>
  <!-- 货币单位本地化 -->
  <td>{{p.price}}</td>
</tr>

这里写图片描述

4.改变字符串大小写

<tr ng-repeat="p in products">
  <!-- 字母大小写 -->
  <td>{{p.name | uppercase}}</td>
  <td>{{p.category | lowercase}}</td>
  <td>{{getExpiryDate(p.expiry) | date : 'yyyy/MM/dd'}}</td>
  <!-- 货币单位本地化 -->
  <td>{{p.price}}</td>
</tr>

这里写图片描述

5.生成JSON

<tr ng-repeat="p in products">
  <!-- 生成JSON数据 -->
  <td>{{p.name | json}}</td>
  <td>{{p.category}}</td>
  <td>{{getExpiryDate(p.expiry) | date : 'yyyy/MM/dd'}}</td>
  <!-- 货币单位本地化 -->
  <td>{{p.price}}</td>
</tr>

这里写图片描述

6.本地化过滤器输出

需要移入本地化JS文件

<!-- 引入本地化文件 -->
<script type="text/javascript" src="js/angular-locale_zh-cn.js"></script>
<tr ng-repeat="p in products">
  <td>{{p.name}}</td>
  <td>{{p.category}}</td>
  <td>{{p.expiry}}</td>
  <!-- 货币单位本地化 -->
  <td>{{p.price | currency}}</td>
</tr>

这里写图片描述

三、过滤集合

1.限制项目的数量―limitTo过滤器

<!DOCTYPE>
<!-- use module -->
<html ng-app="exampleApp">
<head>
  <title>Angluar test</title>
  <meta charset="utf-8"/>
  <link rel="stylesheet" type="text/css" href="css/bootstrap.min.css" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >
  <link rel="stylesheet" type="text/css" href="css/bootstrap-theme.min.css" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >
</head>
<body>
  <dlv class="panel panel-default" ng-controller="defaultCtrl">
    <div class="panel panel-header">
      Products
      <span class="label label-primary">{{products.length}}</span>
    </div>
    <div class="panel panel-body">
      Limit: <select ng-model="limitVal" ng-options="item for item in limitRange"></select>
    </div>
    <div class="panel panel-body">
      <table class="table table-striped table-bordered table-hover">
        <thead>
          <tr><th>Name</th><th>Category</th><th>Expiry</th><th>Price</th></tr>
        </thead>
        <tbody>
          <!-- 只显示limitVal行 -->
          <tr ng-repeat="p in products | limitTo : limitVal">
            <td>{{p.name}}</td>
            <td>{{p.category}}</td>
            <td>{{p.expiry}}</td>
            <td>{{p.price | number : 2}}</td>
          </tr>
        </tbody>
      </table>
    </div>
  </dlv>
<script type="text/javascript" src="js/angular.min.js"></script>
<!-- 引入本地化文件 -->
<script type="text/javascript" src="js/angular-locale_zh-cn.js"></script>
<script type="text/javascript">
var myApp = angular.module("exampleApp", []);
myApp.controller("defaultCtrl", function ($scope) {
  $scope.products = [
    { name: "Apples", category: "Fruit", price: 1.20, expiry: 10 },
    { name: "Bananas", category: "Fruit", price: 2.42, expiry: 7 },
    { name: "Pears", category: "Fruit", price: 2.02, expiry: 6 },
    { name: "Tuna", category: "Fish", price: 20.45, expiry: 3 },
    { name: "Salmon", category: "Fish", price: 17.93, expiry: 2 },
    { name: "Trout", category: "Fish", price: 12.93, expiry: 4 },
    { name: "Beer", category: "Drinks", price: 2.99, expiry: 365 },
    { name: "Wine", category: "Drinks", price: 8.99, expiry: 365 },
    { name: "Whiskey", category: "Drinks", price: 45.99, expiry: 365 }
  ];
  // 显示的条数
  $scope.limitVal = '5';
  // 在限制条数的范围条项
  $scope.limitRange = [];
  for (var i = (0 - $scope.products.length); i <= $scope.products.length; i++) {
    $scope.limitRange.push(i.toString());
  }
})
</script>
</body>
</html>

单击下拉列表，根据提示显示不同的条数，负数表示从后往前取

这里写图片描述

2.选取项―filter过滤器

<!DOCTYPE>
<!-- use module -->
<html ng-app="exampleApp">
<head>
  <title>Angluar test</title>
  <meta charset="utf-8"/>
  <link rel="stylesheet" type="text/css" href="css/bootstrap.min.css" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >
  <link rel="stylesheet" type="text/css" href="css/bootstrap-theme.min.css" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >
</head>
<body>
  <dlv class="panel panel-default" ng-controller="defaultCtrl">
    <div class="panel panel-header">
      Products
      <span class="label label-primary">{{products.length}}</span>
    </div>

    <div class="panel panel-body">
      <table class="table table-striped table-bordered table-hover">
        <thead>
          <tr><th>Name</th><th>Category</th><th>Expiry</th><th>Price</th></tr>
        </thead>
        <tbody>
          <!-- 自定义过滤 -->
          <tr ng-repeat="p in products | filter : selectItems">
            <td>{{p.name}}</td>
            <td>{{p.category}}</td>
            <td>{{p.expiry}}</td>
            <td>{{p.price | number : 2}}</td>
          </tr>
        </tbody>
      </table>
    </div>
  </dlv>
<script type="text/javascript" src="js/angular.min.js"></script>
<!-- 引入本地化文件 -->
<script type="text/javascript" src="js/angular-locale_zh-cn.js"></script>
<script type="text/javascript">
var myApp = angular.module("exampleApp", []);
myApp.controller("defaultCtrl", function ($scope) {
  $scope.products = [
    { name: "Apples", category: "Fruit", price: 1.20, expiry: 10 },
    { name: "Bananas", category: "Fruit", price: 2.42, expiry: 7 },
    { name: "Pears", category: "Fruit", price: 2.02, expiry: 6 },
    { name: "Tuna", category: "Fish", price: 20.45, expiry: 3 },
    { name: "Salmon", category: "Fish", price: 17.93, expiry: 2 },
    { name: "Trout", category: "Fish", price: 12.93, expiry: 4 },
    { name: "Beer", category: "Drinks", price: 2.99, expiry: 365 },
    { name: "Wine", category: "Drinks", price: 8.99, expiry: 365 },
    { name: "Whiskey", category: "Drinks", price: 45.99, expiry: 365 }
  ];
  // 自定义过滤器
  $scope.selectItems = function (item) {
    // 仅仅保留类别为Fish或者name=='Beer'的行
    return item.category == 'Fish' || item.name == 'Beer';
  }

})
</script>
</body>
</html>

仅仅保留类别为Fish或者name=='Beer'的行

这里写图片描述

3.对项目进行排序―orderBy过滤器

<!DOCTYPE>
<!-- use module -->
<html ng-app="exampleApp">
<head>
  <title>Angluar test</title>
  <meta charset="utf-8"/>
  <link rel="stylesheet" type="text/css" href="css/bootstrap.min.css" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >
  <link rel="stylesheet" type="text/css" href="css/bootstrap-theme.min.css" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >
</head>
<body>
  <dlv class="panel panel-default" ng-controller="defaultCtrl">
    <div class="panel panel-header">
      Products
      <span class="label label-primary">{{products.length}}</span>
    </div>

    <div class="panel panel-body">
      <table class="table table-striped table-bordered table-hover">
        <thead>
          <tr><th>Name</th><th>Category</th><th>Expiry</th><th>Price</th></tr>
        </thead>
        <tbody>
          <!-- 通过价格按照升序排列 -->
          <!-- <tr ng-repeat="p in products | orderBy : 'price'"> -->
          <!-- price前加-表示按照降序排列 -->
          <!-- <tr ng-repeat="p in products | orderBy : '-price'"> -->
          <!-- 自定义排序 -->
          <!-- <tr ng-repeat="p in products | orderBy : customOrder"> -->
          <!-- 组合排序，保质期<5的降序排列，其他的按照价格升序排序 -->
          <tr ng-repeat="p in products | orderBy : [customOrder, '-price']">
            <td>{{p.name}}</td>
            <td>{{p.category}}</td>
            <td>{{p.expiry}}</td>
            <td>{{p.price | number : 2}}</td>

          </tr>
        </tbody>
      </table>
    </div>
  </dlv>

<script type="text/javascript" src="js/angular.min.js"></script>
<!-- 引入本地化文件 -->
<script type="text/javascript" src="js/angular-locale_zh-cn.js"></script>
<script type="text/javascript">
var myApp = angular.module("exampleApp", []);
myApp.controller("defaultCtrl", function ($scope) {
  $scope.products = [
    { name: "Apples", category: "Fruit", price: 1.20, expiry: 10 },
    { name: "Bananas", category: "Fruit", price: 2.42, expiry: 7 },
    { name: "Pears", category: "Fruit", price: 2.02, expiry: 6 },

    { name: "Tuna", category: "Fish", price: 20.45, expiry: 3 },
    { name: "Trout", category: "Fish", price: 12.93, expiry: 4 },
    { name: "Salmon", category: "Fish", price: 17.93, expiry: 2 },

    { name: "Beer", category: "Drinks", price: 2.99, expiry: 365 },
    { name: "Wine", category: "Drinks", price: 8.99, expiry: 365 },
    { name: "Whiskey", category: "Drinks", price: 45.99, expiry: 365 }
  ];
  // 自定义函数排序
  $scope.customOrder = function (item) {
    // 保质期<5的不排序，其他的按照价格升序排序
    return item.expiry < 5 ? 0 : item.price;
  }
})
</script>
</body>
</html>

保质期<5的不排序，其他的按照价格升序排序

这里写图片描述 

四、链式过滤器

就是将过滤器串联起来综合使用

<!DOCTYPE>
<!-- use module -->
<html ng-app="exampleApp">
<head>
  <title>Angluar test</title>
  <meta charset="utf-8"/>
  <link rel="stylesheet" type="text/css" href="css/bootstrap.min.css" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >
  <link rel="stylesheet" type="text/css" href="css/bootstrap-theme.min.css" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >
</head>
<body>
  <dlv class="panel panel-default" ng-controller="defaultCtrl">
    <div class="panel panel-header">
      Products
      <span class="label label-primary">{{products.length}}</span>
    </div>

    <div class="panel panel-body">
      <table class="table table-striped table-bordered table-hover">
        <thead>
          <tr><th>Name</th><th>Category</th><th>Expiry</th><th>Price</th></tr>
        </thead>
        <tbody>
          <!-- 过滤链条，通过orderBy和limitTo共同作用 -->
          <tr ng-repeat="p in products | orderBy : [customOrder, '-price'] | limitTo : 5">
            <td>{{p.name}}</td>
            <td>{{p.category}}</td>
            <td>{{p.expiry}}</td>
            <td>{{p.price | number : 2}}</td>

          </tr>
        </tbody>
      </table>
    </div>
  </dlv>

<script type="text/javascript" src="js/angular.min.js"></script>
<!-- 引入本地化文件 -->
<script type="text/javascript" src="js/angular-locale_zh-cn.js"></script>

<script type="text/javascript">

var myApp = angular.module("exampleApp", []);

myApp.controller("defaultCtrl", function ($scope) {
  $scope.products = [
    { name: "Apples", category: "Fruit", price: 1.20, expiry: 10 },
    { name: "Bananas", category: "Fruit", price: 2.42, expiry: 7 },
    { name: "Pears", category: "Fruit", price: 2.02, expiry: 6 },

    { name: "Tuna", category: "Fish", price: 20.45, expiry: 3 },
    { name: "Trout", category: "Fish", price: 12.93, expiry: 4 },
    { name: "Salmon", category: "Fish", price: 17.93, expiry: 2 },

    { name: "Beer", category: "Drinks", price: 2.99, expiry: 365 },
    { name: "Wine", category: "Drinks", price: 8.99, expiry: 365 },
    { name: "Whiskey", category: "Drinks", price: 45.99, expiry: 365 }
  ];
  // 自定义函数排序
  $scope.customOrder = function (item) {
    // 保质期<5的不排序，其他的按照价格升序排序
    return item.expiry < 5 ? 0 : item.price;
  }

})
</script>
</body>
</html>

先按照自定义customOrder函数以price倒序排列，然后只取得5条数据

<tr ng-repeat="p in products | orderBy : [customOrder, '-price'] | limitTo : 5">

这里写图片描述

五、自定义过滤器

1.创建格式化数据值的过滤器

<!DOCTYPE>
<!-- use module -->
<html ng-app="exampleApp">
<head>
  <title>Angluar test</title>
  <meta charset="utf-8"/>
  <link rel="stylesheet" type="text/css" href="css/bootstrap.min.css" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >
  <link rel="stylesheet" type="text/css" href="css/bootstrap-theme.min.css" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >
</head>
<body>
  <dlv class="panel panel-default" ng-controller="defaultCtrl">
    <div class="panel panel-header">
      Products
      <span class="label label-primary">{{products.length}}</span>
    </div>

    <div class="panel panel-body">
      <table class="table table-striped table-bordered table-hover">
        <thead>
          <tr><th>Name</th><th>Category</th><th>Expiry</th><th>Price</th></tr>
        </thead>
        <tbody>

          <tr ng-repeat="p in products">
            <!-- 使用自定义过滤器 -->
            <td>{{p.name | labelCase}}</td>
            <td>{{p.category | labelCase : true}}</td>
            <td>{{p.expiry}}</td>
            <td>{{p.price | number : 2}}</td>
          </tr>
        </tbody>
      </table>
    </div>
  </dlv>

<script type="text/javascript" src="js/angular.min.js"></script>

<script type="text/javascript">

var myApp = angular.module("exampleApp", []);

myApp.controller("defaultCtrl", function ($scope) {
  $scope.products = [
    { name: "Apples", category: "Fruit", price: 1.20, expiry: 10 },
    { name: "Bananas", category: "Fruit", price: 2.42, expiry: 7 },
    { name: "Pears", category: "Fruit", price: 2.02, expiry: 6 },

    { name: "Tuna", category: "Fish", price: 20.45, expiry: 3 },
    { name: "Trout", category: "Fish", price: 12.93, expiry: 4 },
    { name: "Salmon", category: "Fish", price: 17.93, expiry: 2 },

    { name: "Beer", category: "Drinks", price: 2.99, expiry: 365 },
    { name: "Wine", category: "Drinks", price: 8.99, expiry: 365 },
    { name: "Whiskey", category: "Drinks", price: 45.99, expiry: 365 }
  ];
});
</script>
<!-- 引入自定义的过滤器 -->
<script type="text/javascript" src="js/createFilters.js"></script>
</body>
</html>

自定义过滤器，labelCase反转字符串

// js/createFilters.js文件
angular.module("exampleApp")
  .filter("labelCase", function () {
    return function (value, reverse) {
      if (angular.isString(value)) {
        var inter = reverse ? value.toUpperCase() : value.toLowerCase();
        return (reverse ? inter[0].toLowerCase() : inter[0].toUpperCase()) + inter.substr(1);
      } else {
        return value;
      }
    }
  })

这里写图片描述 

2.创建集合过滤器

在createFilter中定义一个skip过滤函数

angular.module("exampleApp")
  .filter("labelCase", function () {
    return function (value, reverse) {
      if (angular.isString(value)) {
        var inter = reverse ? value.toUpperCase() : value.toLowerCase();
        return (reverse ? inter[0].toLowerCase() : inter[0].toUpperCase()) + inter.substr(1);
      } else {
        return value;
      }
    }
  })
  .filter("skip", function () {
    return function (value, count) {
      if (angular.isArray(value) && angular.isNumber(count)){
        if (count > value.length || count < 0) {
          return value;
        } else {
          // 跳过数组前两项
          return value.slice(count);
        }
      } else {
        return value;
      }
    }
  })

在视图中使用

<tr ng-repeat="p in products | skip : 2">
  <!-- 使用自定义过滤器 -->
  <td>{{p.name | labelCase}}</td>
  <td>{{p.category | labelCase : true}}</td>
  <td>{{p.expiry}}</td>
  <td>{{p.price | number : 2}}</td>
</tr>

移除前两项Apples和Bananas，然后显示

这里写图片描述

3.在已有的过滤器上搭建新的过滤器

在createFilter中添加take过滤器返回，将skip和limitTo两个过滤器方法综合起来

angular.module("exampleApp")
  .filter("labelCase", function () {
    return function (value, reverse) {
      if (angular.isString(value)) {
        var inter = reverse ? value.toUpperCase() : value.toLowerCase();
        return (reverse ? inter[0].toLowerCase() : inter[0].toUpperCase()) + inter.substr(1);
      } else {
        return value;
      }
    }
  })
  .filter("skip", function () {
    return function (value, count) {
      if (angular.isArray(value) && angular.isNumber(count)){
        if (count > value.length || count < 0) {
          return value;
        } else {
          // 跳过数组前两项
          return value.slice(count);
        }
      } else {
        return value;
      }
    }
  })
  // 在已有过滤器的基础上建立新的过滤器
  // 将上述的skip和limit两个过滤器合并
  .filter("take", function ($filter) {
    return function (data, skipCount, limitCount) {
      // 先跳过数组的前skipCount项
      var skipData = $filter("skip")(data, skipCount);
      // 接着只取limitCount行
      return $filter("limitTo")(skipData, limitCount);
    }
  })

在视图中使用：

<tr ng-repeat="p in products | take : 2 : 5">
<!-- 使用自定义过滤器 -->
  <td>{{p.name | labelCase}}</td>
  <td>{{p.category | labelCase : true}}</td>
  <td>{{p.expiry}}</td>
  <td>{{p.price | number : 2}}</td>
</tr>

先移除两项，然后值取5条数据

这里写图片描述

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