angular 中表单验证的探索

需求

之前有一段时间做一个搜索查询

但是有很多限制条件，如果校验不成功需要给用户提示错误，当然项目用的是组件库的校验

我能否自己写一个？
其实 我是不会的！！！

探索

angular 的校验功能很强大

自身校验

<form name="$ctrl.myForm">
		<div class="field">
			<input type="email"
				   name="myEmail"
				   minlength="5"
				   maxlength="100"
				   ng-model="$ctrl.myEmail"
				   required />
			<div ng-if="$ctrl.myForm.myEmail.$invalid">There is an error with the field...</div>
		</div>
	</form>

• $pristine (未修改过验证true)
• $dirty (修改过为true)
• $valid (通过验证)
• $invalid (未经过验证)

我们可以创建自定义的ngModel在ngModelController中实现验证。
angular中通过$validators来实现验证

 var m1 = angular.module('app', []);
 m1.controller('customValidator', function () {
   require: 'ngModel',
   link: function () { scope, element, attrs, ngModel} {
        ngModel.$validators.myValidator = function () {
                ......   
        }
    }
})

自定义校验

在angularJs中使用$validators来实现表单的验证

m1.directive('validatePasswordCharacters', function() {
            var REQUIRED_PATTERNS = [
                /\d+/,
                /[a-z]+/,
                /[A-Z]+/,
                /\W+/,
                /^\S+$/
            ];
            return {
                require : 'ngModel',
                link : function($scope, element, attrs, ngModel) {
                    ngModel.$validators.passwordCharacters = function(value) {
                        var status = true;
                        angular.forEach(REQUIRED_PATTERNS, function(pattern) {
                            status = status && pattern.test(value);
                        });
                        return status;
                    };
                }
            }
        });

<form name="myForm">
        <div class="label">
            <input name="myPassword" type="password" ng-model="data.password" validate-password-characters required />
            <div ng-if="myForm.myPassword.$error.required && myForm.myPassword.$dirty">
                You did not enter a password
            </div>
            <div ng-if="myForm.myPassword.$error.passwordCharacters && myForm.myPassword.$dirty">
                Your password must contain a numeric, uppercase and lowercase as well as special characters
            </div>
        </div>
    </form>

结果
没有输入之前

随意输入

异步校验

通过异步ajax与后台胡来判断用户的输入

ngModule.directive('usernameAvailableValidator', ['$http', function($http) {
    return {
        require : 'ngModel',
        link : function($scope, element, attrs, ngModel) {
            ngModel.$asyncValidators.usernameAvailable = function(username) {
                return $http.get('/api/username-exists?u='+ username);
            };
        }
    }
    }]);

异步校验器$asyncValidators在触发的时候需要每个验证器返回一个promise对象。当promise完成的时候便是通过，reject的时候把错误注册到$error对象上。
当所有验证器通过，值才写入scope.
异步验证期间$valid和$invalide为undefined, 会有一个特殊标志$pending来表示，异步验证完成被移除。

<form name="myForm">
    <input type="text"
        class="input"
        name="username"
        minlength="4"
        maxlength="15"
        ng-model="form.data.username"
        pattern="^[-\w]+$"
        username-available-validator
        placeholder="Choose a username for yourself"
        required />
    <div ng-if="myForm.username.$pending">
        Checking Username...
    </div>
    <!-- ... -->
</form>

使用ngMessage来显示错误

<form name="myForm">
        <input type="text" name="colorCode" ng-model="data.colorCode" minlength="6" required>
        <div ng-message="myForm.colorCode.$error" ng-if="myForm.$submitted || myForm.colorCode.$touched">
            <div ng-message="required">22.</div>
            <div ng-message="minlength">333...</div>
            <div ng-message="pattern">444...</div>
        </div>
        <nav class="actions">
            <input type="submit" />
        </nav>
    </form>

<script type="text/javascript">
    var ngModule = angular.module('myApp', ['ngMessages']);
</script>

当然 如果ng-message 无法满足错误提示的需求 也可以用ng-message-include

<div ng-message-include='toolTpl'></div>

以上！！！
最后我的愿望