名称为"ngMessages"的module，通过npm install angular-messages进行安装。在没有使用ngMessages之前，我们可能这样写验证：
<form name="userForm">
<input
type="text"
name="username"
ng-model="user.username"
ng-minlength="3"
ng-maxlength="8"
required>
<p ng-show="userForm.username.$error.minlength">Username is too short.</p>
<p ng-show="userForm.username.$error.maxlength">Username is too long.</p>
<p ng-show="userForm.username.$error.required">Your username is required.</p>
</form>
以上，列举了每种可能的验证失败，并且手工编写是否显示错误提示信息。
有了"ngMessages"这个module,大致这么写：
<div class="help-block" ng-messages="userForm.name.$error" ng-if="userForm.name.$touched">
<p ng-message="minlength">用户名最小长度5</p>
<p ng-message="maxlength">用户名最大长度10</p>
<p ng-message="required">用户名必填</p>
</div>
ngMessages为我们自动判断显示哪种错误。
使用ngMessages的几个关键点：
● npm install angular-messages
● 引用：angular-messages.js
● 依赖：angular.module('app',['ngMessages'])
这里有一个简单的Demo,文件结构：
node_modules/
app.js
emailmessages.html
index.html
安装如下：
npm install bootstrap
npm install angular
npm install angular-messages
==index.html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title></title>
<link rel="stylesheet" href="node_modules/bootstrap/dist/css/bootstrap.min.css"/>
<style>
body{
padding-top: 50px;
}
</style>
</head>
<body class="container" ng-app="app" ng-controller="MainCtrl as main"> <form name="userForm" novalidate> <div class="form-group" ng-class="{'has-error':userForm.name.$touched && userForm.name.$invalid}">
<label>用户名</label>
<input type="text" name="name" class="form-control"
ng-model="main.name"
ng-minlength="5"
ng-maxlength="10" required/> <div class="help-block" ng-messages="userForm.name.$error" ng-if="userForm.name.$touched">
<p ng-message="minlength">用户名最小长度5</p>
<p ng-message="maxlength">用户名最大长度10</p>
<p ng-message="required">用户名必填</p>
</div>
</div> <div class="form-group" ng-class="{'has-error':userForm.email.$touched && userForm.email.$invalid}">
<label>邮箱</label>
<input type="email" name="email" class="form-control"
ng-model="main.email"
ng-minlength="5"
ng-maxlength="20" required/> <div class="help-block" ng-messages="userForm.email.$error" ng-if="userForm.email.$touched">
<div ng-messages-include="emailmessages.html"></div>
</div>
</div> <div class="form-group">
<button type="submit" class="btn btn-danger">提交</button>
</div> <pre>{{userForm.name.$error}}</pre>
<pre>{{userForm.email.$error}}</pre>
</form> <script src="node_modules/angular/angular.min.js"></script>
<script src="node_modules/angular-messages/angular-messages.js"></script>
<script src="app.js"></script>
</body>
</html>
app.js
angular.module('app',['ngMessages'])
.controller('MainCtrl', MainCtrl);
function MainCtrl(){
}
emailmessages.html
把有关email的表单验证放在这里，通过<div ng-messages-include="emailmessages.html"></div>显示到页面某个位置上。
<p ng-message="required">邮箱必填</p>
<p ng-message="minlength">邮箱长度太短</p>
<p ng-message="maxlength">邮箱长度太长</p>
<p ng-message="email">邮箱无效</p>