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AngularJS variable and filter usage analysis

高洛峰

Dec 05, 2016 pm 05:06 PM

angularjs

The examples in this article describe the usage of AngularJS variables and filters. Share it with everyone for your reference, the details are as follows:

1. About the operation of some variables

Set variables:

ng-init="hour=14" //设置hour变量在DOM中 使用data-ng-init 更好些
$scope.hour = 14; //设置hour变量在js中

Use variables:

(1) If it is DOM related ng-*** Write the variable name directly in the attribute

such as:

<p ng-show="hour > 13">I am visible.</p>

(2) If it is in the controller HTML but not in the ng attribute

use {{variable name}}

such as:

{{hour}}

(3) Of course, the third way is to use the above in js

plus the object name $scope.

$scope.hour

(4) In the form control, the variables in ng-model can be directly

at the same time Use {{variable name}} in html

<p>Name: <input type="text" ng-model="name"></p>
<p>You wrote: {{ name }}</p>

You can also bind variables through the ng-bind attribute

<p>Name: <input type="text" ng-model="name"></p>
<p ng-bind="name"></p>

(5) You can use expressions directly in ng attributes or variables

will automatically help you calculate the required js syntax

ng-show="true?false:true"
{{5+6}}
<div ng-app="" ng-init="points=[1,15,19,2,40]">
  <p>The third result is <span ng-bind="points[2]"></span></p>
</div>

2. Variable loop in js

<div ng-app="" ng-init="names=[&#39;Jani&#39;,&#39;Hege&#39;,&#39;Kai&#39;]">
 <ul>
  <li ng-repeat="x in names">
   {{ x }}
  </li>
 </ul>
</div>

3. Variable filter

Filter Format numbers in financial format
filter Select to filter a subset from an array item.
lowercase Lowercase
orderBy Sort the array by expression
uppercase Uppercase

Such as:

<p>The name is {{ lastName | uppercase }}</p>

Of course, multiple function packages can be used |

<p>The name is {{ lastName | uppercase | lowercase }}</p>
//排序函数的使用
<ul>
 <li ng-repeat="x in names | orderBy:&#39;country&#39;">
  {{ x.name + &#39;, &#39; + x.country }}
 </li>
</ul>
//通过输入内容自动过滤显示结果
<div ng-app="" ng-controller="namesCtrl">
  <p><input type="text" ng-model="test"></p>
  <ul>
   <li ng-repeat="x in names | filter:test | orderBy:&#39;country&#39;">
    {{ (x.name | uppercase) + &#39;, &#39; + x.country }}
   </li>
  </ul>
</div>

names | filter:test | orderBy:'country '

is to filter the items in the names array according to the test form value
and then sort by the sub-element country in names

Custom filter:

<!DOCTYPE html>
<html ng-app="HelloApp">
<head>
<title></title>
</head>
<body ng-controller="HelloCtrl">
 <form>
   <input type="text" ng-model="name"/>
 </form>
 <div>{{name|titlecase}}</div>
 <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>
 <script type="text/javascript">
  // 编写过滤器模块
  angular.module(&#39;CustomFilterModule&#39;, [])
      .filter( &#39;titlecase&#39;, function() {
    return function( input ) {
      return input.replace(/\w\S*/g, function(txt){return txt.charAt(0).toUpperCase() + txt.substr(1).toLowerCase();});
  }
  });
  // 实际展示模块
  // 引入依赖的过滤器模块 CustomFilterModule
  angular.module(&#39;HelloApp&#39;, [ &#39;CustomFilterModule&#39;])
    .controller(&#39;HelloCtrl&#39;, [&#39;$scope&#39;, function($scope){
    $scope.name = &#39;&#39;;
  }])
</script>
</body>
</html>

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