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AngularJS provides what they call 'model flags' on their forms. For example, you can have formName.$dirty, formName.$invalid, etc. What I want to know is how can I create my own custom flag for my AngularJS forms? A high level demonstration or link to an article would be a sufficient answer.
See here: how-to-add-custom-validation-to-an-angular-js-form.
In short, this is a custom valitation directive example:
app.directive('blacklist', function (){
return {
require: 'ngModel',
link: function(scope, elem, attr, ngModel) {
var blacklist = attr.blacklist.split(',');
// for DOM -> model validation
ngModel.$parsers.unshift(function(value) {
var valid = blacklist.indexOf(value) === -1;
ngModel.$setValidity('blacklist', valid);
return valid ? value : undefined;
});
//For model -> DOM validation
ngModel.$formatters.unshift(function(value) {
ngModel.$setValidity('blacklist', blacklist.indexOf(value) === -1);
return value;
});
}
};
});
And this it's an example of it's usage:
<form name="myForm" ng-submit="doSomething()">
<input type="text" name="fruitName" ng-model="data.fruitName" blacklist="coconuts,bananas,pears" required/>
<span ng-show="myForm.fruitName.$error.blacklist">
The phrase "{{data.fruitName}}" is blacklisted</span>
<span ng-show="myForm.fruitName.$error.required">required</span>
<button type="submit" ng-disabled="myForm.$invalid">Submit</button>
</form>
But, again, read the referenced question and accepted answer, it's by far more complete...
I have created one custom directive to validate the "domain" name form field.
form field element as
<input type="text" autofocus name="domain" ng-model="user.domain" domain-validate="/^[a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,4})$/" >
custom directive code is
app.directive('domainValidate', function() {
return {
// element must have ng-model attribute.
require: 'ngModel',
// scope = the parent scope
// elem = the element the directive is on
// attr = a dictionary of attributes on the element
// ctrl = the controller for ngModel.
link: function(scope, elem, attr, ctrl) {
//get the regex flags from the regex-validate-flags="" attribute (optional)
var flags = attr.domainValidateFlags || 'i';
// create the regex obj.
var regex = new RegExp(attr.domainValidate, flags);
// add a parser that will process each time the value is
// parsed into the model when the user updates it.
ctrl.$parsers.unshift(function(value) {
// test and set the validity after update.
var valid = regex.test(value);
ctrl.$setValidity('domainValidate', valid);
// if it's valid, return the value to the model,
// otherwise return undefined.
return valid ? value : undefined;
});
// add a formatter that will process each time the value
// is updated on the DOM element.
ctrl.$formatters.unshift(function(value) {
// validate.
console.log(value)
ctrl.$setValidity('domainValidate', regex.test(value));
// return the value or nothing will be written to the DOM.
return value;
});
}
};
});
I want to validate the field on form submit as well on value change.
The above code is not working, please can any one help me what is the error in above code or
let me know how to validate the domain name field
thanks
oldish post and i'm noob at angular, but try this
<form name="userForm" ng-submit="submit()" novalidate>
<div>
<input type="text" autofocus name="domain" ng-model="user.domain" domain-validate="^([a-zA-Z0-9]([a-zA-Z0-9\-]{0,61}[a-zA-Z0-9])?\.)+[a-zA-Z]{2,63}$" required>
<div ng-show="userForm.domain.$error.domainValidate">invalid domain</div>
<div ng-show="userForm.domain.$dirty && userForm.domain.$error.required">required</div>
</div>
<button type="submit">Submit</button>
</form>
then js directive
app.directive('domainValidate', function () {
return {
require: 'ngModel',
link: function (scope, elem, attr, ctrl) {
//get the regex flags from the regex-validate-flags="" attribute (optional)
var flags = attr.domainValidateFlags || 'i';
// create the regex obj.
var regex = new RegExp(attr.domainValidate, flags);
function setValidity(value) {
ctrl.$setValidity('domainValidate', regex.test(value));
}
scope.$watch(attr.ngModel, function (newValue, oldValue) {
if (newValue !== undefined && newValue !== oldValue) {
setValidity(newValue);
}
});
scope.submit = function () {
setValidity(ctrl.$modelValue);
for (var error in ctrl.$error) {
if (ctrl.$error[error]) return;
}
// send stuff
}
}
};
});
My suggestion is: Instead of custom directive validation use default URL validation:
<input type="url" autofocus name="domain" ng-model="user.domain">
Or if you don't want to use it, share your code in fiddle.
I'm trying to write my own set of directives. I have written following two directives:
eaValidateEmail (Validates the format of the email address)
eaValidateUnique (Will validate the uniqueness by a call to a rest service once complete)
What I want to achieve:
First the eaValidateEmail directive is executed which returns false until the format of the email is correct
Then and only then the eaValidateUnique directive should execute and check if the email address is taken already over a rest service. If the value is not found it will return true, else it will return false.
What's happening
When I only add the eaValidateEmail directive, everything is working and the format of the email is validated.
But as soon I add the eaValidateUnique directive then the eaValidateEmail directive is left out and the ctrl.$valid method of the eaValidateUnique directive is always passing even though ctrl.$valid is false in console.log.
I have read through the AngularJS documentation, bought two books but the examples are always very basic. Currently I can't figure out where the problem could be located. It looks like there is a clash with ngModelController but I can't figure out the right way to solve this issue.
I'm currently testing with the ValidateCtrlNew form. So the field in the "New" section of the html form.
Questions:
Does anybody know how to write the directives so that they are executed in serial order as I add them as attributes to the input element?
How can I prevent such clashes with directives? Isolated scope is also no option for multiple directives.
Here is the jsfiddle: http://jsfiddle.net/charms/6j3U8/230/
<div ng-controller="ValidateCtrlNew">
<form name="user_form_new" class="pure-form" novalidate>
<fieldset>
<legend>New</legend>
<input type="text" name="email" ng-model="user.email" placeholder="E-Mail" class="txt_fld" ng-required="true" ea-validate-email ea-validate-unique/><br/>
<div class="inv_msg" ng-show="user_form_new.email.$dirty && user_form_new.email.$invalid">Invalid:
<span ng-show="user_form_new.email.$error.required">Please enter your email.</span>
<span ng-show="user_form_new.email.$error.eaValidateEmail">This is not a valid email.</span>
<span ng-show="user_form_new.email.$error.eaValidateEmailCheck">Checking email....</span>
<span ng-show="user_form_new.email.$error.eaValidateUnique">This email is already taken.</span>
</div>
</fieldset>
</form>
</div>
.directive('eaValidateUnique', ['$http', function($http) {
return {
restrict: 'A',
require: 'ngModel',
link: function(scope, elem, attr, ctrl) {
ctrl.$parsers.push(function(viewValue) {
console.log(ctrl);
//ctrl.$setValidity('eaValidateUnique', true);
if(ctrl.$valid) {
ctrl.$setValidity('eaValidateUnique', false);
console.log("valid was true");
}
});
}
};
}])
.directive('eaValidateEmail', [function() {
return {
restrict: 'A',
require: 'ngModel',
link: function(scope, elem, attr, ctrl) {
var EMAIL_REGEXP = /^([\w-\.]+)#((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([\w-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$/;
ctrl.$parsers.push(function(viewValue) {
// set validity to true to clear out if previous validators fail
ctrl.$setValidity('eaValidateEmail', true);
if(ctrl.$valid) {
// set validity to false as we need to check the value here
ctrl.$setValidity('eaValidateEmail', false);
if(viewValue !== undefined && viewValue !== "" && EMAIL_REGEXP.test(viewValue)) {
// if the format of the email is valid then we set validity to true
ctrl.$setValidity('eaValidateEmail', true);
ctrl.$setValidity('eaValidateEmailCheck', true);
console.log("TRUE");
} else {
// if the format of the email is invalid we set validity to false
ctrl.$setValidity('eaValidateEmail', false);
ctrl.$setValidity('eaValidateEmailCheck', true);
console.log("FALSE");
}
}
return viewValue;
});
}
};
}]);
you can add priority to eaValidateEmail to 100 like..
restrict: 'A',
priority:'100',
require: 'ngModel',
From what I understand is that the validators are chained on the $parsers array. AngularJs validators return the value if the validator decides the value if valid, but return an undefined if the value is invalid.
This way, the other validators on your chain would not have a value to work with anymore.
http://docs.angularjs.org/api/ng.directive:ngModel.NgModelController#$parsers
How would you go about disabling, or at the very least changing, how Angular validates type=email inputs?
Currently, if you use type=email, Angular essentially double validates.. as the Browser (Chrome in this case) validates the email, and then angular does too. Not only that, but what is valid in Chrome foo#bar is not valid in Angularjs.
The best i could find, is ng-pattern, but ng-pattern simply adds a 3rd pattern validation for the input type.. instead of replacing Angular's email validation. heh
Any ideas?
Note: This is example is for angular 1.2.0-rc.3. Things might behave differently on other versions
Like others have stated it is a bit complex to turn off angulars default input validation. You need to add your own directive to the input element and handle things in there. Sergey's answer is correct, however it presents some problems if you need several validators on the element and don't want the built in validator to fire.
Here is an example validating an email field with a required validator added. I have added comments to the code to explain what is going on.
Input element
<input type="email" required>
Directive
angular.module('myValidations', [])
.directive('input', function () {
var self = {
// we use ?ngModel since not all input elements
// specify a model, e.g. type="submit"
require: '?ngModel'
// we need to set the priority higher than the base 0, otherwise the
// built in directive will still be applied
, priority: 1
// restrict this directive to elements
, restrict: 'E'
, link: function (scope, element, attrs, controller) {
// as stated above, a controller may not be present
if (controller) {
// in this case we only want to override the email validation
if (attrs.type === 'email') {
// clear this elements $parsers and $formatters
// NOTE: this will disable *ALL* previously set parsers
// and validators for this element. Beware!
controller.$parsers = [];
controller.$formatters = [];
// this function handles the actual validation
// see angular docs on how to write custom validators
// http://docs.angularjs.org/guide/forms
//
// in this example we are not going to actually validate an email
// properly since the regex can be damn long, so apply your own rules
var validateEmail = function (value) {
console.log("Validating as email", value);
if (controller.$isEmpty(value) || /#/.test(value)) {
controller.$setValidity('email', true);
return value;
} else {
controller.$setValidity('email', false);
return undefined;
}
};
// add the validator to the $parsers and $formatters
controller.$parsers.push(validateEmail);
controller.$formatters.push(validateEmail);
}
}
}
};
return self;
})
// define our required directive. It is a pretty standard
// validation directive with the exception of it's priority.
// a similar approach must be take with all validation directives
// you would want to use alongside our `input` directive
.directive('required', function () {
var self = {
// required should always be applied to a model element
require: 'ngModel'
, restrict: 'A'
// The priority needs to be higher than the `input` directive
// above, or it will be removed when that directive is run
, priority: 2
, link: function (scope, element, attrs, controller) {
var validateRequired = function (value) {
if (value) {
// it is valid
controller.$setValidity('required', true);
return value;
} else {
// it is invalid, return undefined (no model update)
controller.$setValidity('required', false);
return undefined;
}
};
controller.$parsers.push(validateRequired);
}
};
return self;
})
;
There you have it. You now have control over type="email" input validations. Please use a proper regex to test the email though.
One thing to note is that in this example validateEmail is run before validateRequired. If you need validateRequired to run before any other validations, then just prepend it to the $parsers array (using unshift instead of push).
Very simple. I had to alter the email regex to match a business requirement, so I made this directive that makes the email regex customizable. It essentially overwrites the original validator with my custom one. You don't have to mess with all the $parsers and $formatters (unless I'm missing something). So my directive was this...
module.directive('emailPattern', function(){
return {
require : 'ngModel',
link : function(scope, element, attrs, ngModel) {
var EMAIL_REGEX = new RegExp(attrs.emailPattern, "i");
ngModel.$validators["email"] = function (modelValue, viewValue) {
var value = modelValue || viewValue;
return ngModel.$isEmpty(value) || EMAIL_REGEX.test(value);
};
}
}
});
Then use it like this, supplying whatever email pattern you personally want:
<input type="email" email-pattern=".+#.+\..+"/>
But if you just want to permanently disable it then you could do this.
module.directive('removeNgEmailValidation', function(){
return {
require : 'ngModel',
link : function(scope, element, attrs, ngModel) {
ngModel.$validators["email"] = function () {
return true;
};
}
}
});
Then use it like this...
<input type="email" remove-ng-email-validation>
On HTML5 you can use the form's attribute novalidate to disable browser's validation:
<form novalidate>
<input type="email"/>
</form>
If you want to create a custom validator in angularjs, you have a good tutorial and example here: http://www.benlesh.com/2012/12/angular-js-custom-validation-via.html
Echoing nfiniteloop, you don't need to mess with the $parsers or $formatters to override the default validators. As referenced in the Angular 1.3 docs, the $validators object is accessible on the ngModelController. With custom directives you can write as many different email validation functions as you need and call them wherever you want.
Here's one with a very nice standard email format regex from tuts: 8 Regular Expressions You Should Now (probably identical to Angular's default, idk).
var app = angular.module('myApp', []);
app.directive('customEmailValidate', function() {
return {
require: 'ngModel',
link: function(scope, elm, attrs, ctrl) {
var EMAIL_REGEXP = /^([a-z0-9_\.-]+)#([\da-z\.-]+)\.([a-z\.]{2,6})$/;
ctrl.$validators.email = function(modelValue, viewValue) {
if (ctrl.$isEmpty(modelValue)) {
// consider empty models to be valid
return true;
}
if (EMAIL_REGEXP.test(viewValue)) {
// it is valid
return true;
}
// it is invalid
return false;
};
}
};
});
Here's one that removes validation entirely:
var app = angular.module('myApp', []);
app.directive('noValidation', function() {
return {
require: 'ngModel',
link: function(scope, elm, attrs, ctrl) {
ctrl.$validators.email = function(modelValue, viewValue) {
// everything is valid
return true;
};
}
};
});
To use in your markup:
<!-- 'test#example.com' is valid, '#efe#eh.c' is invalid -->
<input type="email" custom-email-validate>
<!-- both 'test#example.com' and '#efe#eh.c' are valid -->
<input type="email" no-validation>
In my project I do something like this (custom directive the erases all other validations including ones installed by angularjs):
angular.module('my-project').directive('validEmail', function() {
return {
require: 'ngModel',
link: function(scope, elm, attrs, ctrl){
var validator = function(value){
if (value == '' || typeof value == 'undefined') {
ctrl.$setValidity('validEmail', true);
} else {
ctrl.$setValidity('validEmail', /your-regexp-here/.test(value));
}
return value;
};
// replace all other validators!
ctrl.$parsers = [validator];
ctrl.$formatters = [validator];
}
}
});
How to use it (note novalidate, it's required to turn off browser validation):
<form novalidate>
<input type="email" model="email" class="form-control" valid-email>
I have a form with input fields and validation setup by adding the required attributes and such. But for some fields I need to do some extra validation. How would I "tap in" to the validation that FormController controls?
Custom validation could be something like "if these 3 fields are filled in, then this field is required and needs to be formatted in a particular way".
There's a method in FormController.$setValidity but that doesn't look like a public API so I rather not use it. Creating a custom directive and using NgModelController looks like another option, but would basically require me to create a directive for each custom validation rule, which I do not want.
Actually, marking a field from the controller as invalid (while also keeping FormController in sync) might be the thing that I need in the simplest scenario to get the job done, but I don't know how to do that.
Edit: added information about ngMessages (>= 1.3.X) below.
Standard form validation messages (1.0.X and above)
Since this is one of the top results if you Google "Angular Form Validation", currently, I want to add another answer to this for anyone coming in from there.
There's a method in FormController.$setValidity but that doesn't look like a public API so I rather not use it.
It's "public", no worries. Use it. That's what it's for. If it weren't meant to be used, the Angular devs would have privatized it in a closure.
To do custom validation, if you don't want to use Angular-UI as the other answer suggested, you can simply roll your own validation directive.
app.directive('blacklist', function (){
return {
require: 'ngModel',
link: function(scope, elem, attr, ngModel) {
var blacklist = attr.blacklist.split(',');
//For DOM -> model validation
ngModel.$parsers.unshift(function(value) {
var valid = blacklist.indexOf(value) === -1;
ngModel.$setValidity('blacklist', valid);
return valid ? value : undefined;
});
//For model -> DOM validation
ngModel.$formatters.unshift(function(value) {
ngModel.$setValidity('blacklist', blacklist.indexOf(value) === -1);
return value;
});
}
};
});
And here's some example usage:
<form name="myForm" ng-submit="doSomething()">
<input type="text" name="fruitName" ng-model="data.fruitName" blacklist="coconuts,bananas,pears" required/>
<span ng-show="myForm.fruitName.$error.blacklist">
The phrase "{{data.fruitName}}" is blacklisted</span>
<span ng-show="myForm.fruitName.$error.required">required</span>
<button type="submit" ng-disabled="myForm.$invalid">Submit</button>
</form>
Note: in 1.2.X it's probably preferrable to substitute ng-if for ng-show above
Here is an obligatory plunker link
Also, I've written a few blog entries about just this subject that goes into a little more detail:
Angular Form Validation
Custom Validation Directives
Edit: using ngMessages in 1.3.X
You can now use the ngMessages module instead of ngShow to show your error messages. It will actually work with anything, it doesn't have to be an error message, but here's the basics:
Include <script src="angular-messages.js"></script>
Reference ngMessages in your module declaration:
var app = angular.module('myApp', ['ngMessages']);
Add the appropriate markup:
<form name="personForm">
<input type="email" name="email" ng-model="person.email" required/>
<div ng-messages="personForm.email.$error">
<div ng-message="required">required</div>
<div ng-message="email">invalid email</div>
</div>
</form>
In the above markup, ng-message="personForm.email.$error" basically specifies a context for the ng-message child directives. Then ng-message="required" and ng-message="email" specify properties on that context to watch. Most importantly, they also specify an order to check them in. The first one it finds in the list that is "truthy" wins, and it will show that message and none of the others.
And a plunker for the ngMessages example
Angular-UI's project includes a ui-validate directive, which will probably help you with this. It let's you specify a function to call to do the validation.
Have a look at the demo page: http://angular-ui.github.com/, search down to the Validate heading.
From the demo page:
<input ng-model="email" ui-validate='{blacklist : notBlackListed}'>
<span ng-show='form.email.$error.blacklist'>This e-mail is black-listed!</span>
then in your controller:
function ValidateCtrl($scope) {
$scope.blackList = ['bad#domain.example','verybad#domain.example'];
$scope.notBlackListed = function(value) {
return $scope.blackList.indexOf(value) === -1;
};
}
You can use ng-required for your validation scenario ("if these 3 fields are filled in, then this field is required":
<div ng-app>
<input type="text" ng-model="field1" placeholder="Field1">
<input type="text" ng-model="field2" placeholder="Field2">
<input type="text" ng-model="field3" placeholder="Field3">
<input type="text" ng-model="dependentField" placeholder="Custom validation"
ng-required="field1 && field2 && field3">
</div>
You can use Angular-Validator.
Example: using a function to validate a field
<input type = "text"
name = "firstName"
ng-model = "person.firstName"
validator = "myCustomValidationFunction(form.firstName)">
Then in your controller you would have something like
$scope.myCustomValidationFunction = function(firstName){
if ( firstName === "John") {
return true;
}
You can also do something like this:
<input type = "text"
name = "firstName"
ng-model = "person.firstName"
validator = "'!(field1 && field2 && field3)'"
invalid-message = "'This field is required'">
(where field1 field2, and field3 are scope variables. You might also want to check if the fields do not equal the empty string)
If the field does not pass the validator then the field will be marked as invalid and the user will not be able to submit the form.
For more use cases and examples see: https://github.com/turinggroup/angular-validator
Disclaimer: I am the author of Angular-Validator
I recently created a directive to allow for expression-based invalidation of angular form inputs. Any valid angular expression can be used, and it supports custom validation keys using object notation. Tested with angular v1.3.8
.directive('invalidIf', [function () {
return {
require: 'ngModel',
link: function (scope, elm, attrs, ctrl) {
var argsObject = scope.$eval(attrs.invalidIf);
if (!angular.isObject(argsObject)) {
argsObject = { invalidIf: attrs.invalidIf };
}
for (var validationKey in argsObject) {
scope.$watch(argsObject[validationKey], function (newVal) {
ctrl.$setValidity(validationKey, !newVal);
});
}
}
};
}]);
You can use it like this:
<input ng-model="foo" invalid-if="{fooIsGreaterThanBar: 'foo > bar',
fooEqualsSomeFuncResult: 'foo == someFuncResult()'}/>
Or by just passing in an expression (it will be given the default validationKey of "invalidIf")
<input ng-model="foo" invalid-if="foo > bar"/>
Here's a cool way to do custom wildcard expression validations in a form (from: Advanced form validation with AngularJS and filters):
<form novalidate="">
<input type="text" id="name" name="name" ng-model="newPerson.name"
ensure-expression="(persons | filter:{name: newPerson.name}:true).length !== 1">
<!-- or in your case:-->
<input type="text" id="fruitName" name="fruitName" ng-model="data.fruitName"
ensure-expression="(blacklist | filter:{fruitName: data.fruitName}:true).length !== 1">
</form>
app.directive('ensureExpression', ['$http', '$parse', function($http, $parse) {
return {
require: 'ngModel',
link: function(scope, ele, attrs, ngModelController) {
scope.$watch(attrs.ngModel, function(value) {
var booleanResult = $parse(attrs.ensureExpression)(scope);
ngModelController.$setValidity('expression', booleanResult);
});
}
};
}]);
jsFiddle demo (supports expression naming and multiple expressions)
It's similar to ui-validate, but you don't need a scope specific validation function (this works generically) and ofcourse you don't need ui.utils this way.
#synergetic I think #blesh suppose to put function validate as below
function validate(value) {
var valid = blacklist.indexOf(value) === -1;
ngModel.$setValidity('blacklist', valid);
return valid ? value : undefined;
}
ngModel.$formatters.unshift(validate);
ngModel.$parsers.unshift(validate);
Update:
Improved and simplified version of previous directive (one instead of two) with same functionality:
.directive('myTestExpression', ['$parse', function ($parse) {
return {
restrict: 'A',
require: 'ngModel',
link: function (scope, element, attrs, ctrl) {
var expr = attrs.myTestExpression;
var watches = attrs.myTestExpressionWatch;
ctrl.$validators.mytestexpression = function (modelValue, viewValue) {
return expr == undefined || (angular.isString(expr) && expr.length < 1) || $parse(expr)(scope, { $model: modelValue, $view: viewValue }) === true;
};
if (angular.isString(watches)) {
angular.forEach(watches.split(",").filter(function (n) { return !!n; }), function (n) {
scope.$watch(n, function () {
ctrl.$validate();
});
});
}
}
};
}])
Example usage:
<input ng-model="price1"
my-test-expression="$model > 0"
my-test-expression-watch="price2,someOtherWatchedPrice" />
<input ng-model="price2"
my-test-expression="$model > 10"
my-test-expression-watch="price1"
required />
Result: Mutually dependent test expressions where validators are executed on change of other's directive model and current model.
Test expression has local $model variable which you should use to compare it to other variables.
Previously:
I've made an attempt to improve #Plantface code by adding extra directive. This extra directive very useful if our expression needs to be executed when changes are made in more than one ngModel variables.
.directive('ensureExpression', ['$parse', function($parse) {
return {
restrict: 'A',
require: 'ngModel',
controller: function () { },
scope: true,
link: function (scope, element, attrs, ngModelCtrl) {
scope.validate = function () {
var booleanResult = $parse(attrs.ensureExpression)(scope);
ngModelCtrl.$setValidity('expression', booleanResult);
};
scope.$watch(attrs.ngModel, function(value) {
scope.validate();
});
}
};
}])
.directive('ensureWatch', ['$parse', function ($parse) {
return {
restrict: 'A',
require: 'ensureExpression',
link: function (scope, element, attrs, ctrl) {
angular.forEach(attrs.ensureWatch.split(",").filter(function (n) { return !!n; }), function (n) {
scope.$watch(n, function () {
scope.validate();
});
});
}
};
}])
Example how to use it to make cross validated fields:
<input name="price1"
ng-model="price1"
ensure-expression="price1 > price2"
ensure-watch="price2" />
<input name="price2"
ng-model="price2"
ensure-expression="price2 > price3"
ensure-watch="price3" />
<input name="price3"
ng-model="price3"
ensure-expression="price3 > price1 && price3 > price2"
ensure-watch="price1,price2" />
ensure-expression is executed to validate model when ng-model or any of ensure-watch variables is changed.
Custom Validations that call a Server
Use the ngModelController $asyncValidators API which handles asynchronous validation, such as making an $http request to the backend. Functions added to the object must return a promise that must be resolved when valid or rejected when invalid. In-progress async validations are stored by key in ngModelController.$pending. For more information, see AngularJS Developer Guide - Forms (Custom Validation).
ngModel.$asyncValidators.uniqueUsername = function(modelValue, viewValue) {
var value = modelValue || viewValue;
// Lookup user by username
return $http.get('/api/users/' + value).
then(function resolved() {
//username exists, this means validation fails
return $q.reject('exists');
}, function rejected() {
//username does not exist, therefore this validation passes
return true;
});
};
For more information, see
ngModelController $asyncValidators API
AngularJS Developer Guide - Forms (Custom Validation).
Using the $validators API
The accepted answer uses the $parsers and $formatters pipelines to add a custom synchronous validator. AngularJS 1.3+ added a $validators API so there is no need to put validators in the $parsers and $formatters pipelines:
app.directive('blacklist', function (){
return {
require: 'ngModel',
link: function(scope, elem, attr, ngModel) {
ngModel.$validators.blacklist = function(modelValue, viewValue) {
var blacklist = attr.blacklist.split(',');
var value = modelValue || viewValue;
var valid = blacklist.indexOf(value) === -1;
return valid;
});
}
};
});
For more information, see AngularJS ngModelController API Reference - $validators.
In AngularJS the best place to define Custom Validation is Cutsom directive.
AngularJS provide a ngMessages module.
ngMessages is a directive that is designed to show and hide messages
based on the state of a key/value object that it listens on. The
directive itself complements error message reporting with the ngModel
$error object (which stores a key/value state of validation errors).
For custom form validation One should use ngMessages Modules with custom directive.Here i have a simple validation which will check if number length is less then 6 display an error on screen
<form name="myform" novalidate>
<table>
<tr>
<td><input name='test' type='text' required ng-model='test' custom-validation></td>
<td ng-messages="myform.test.$error"><span ng-message="invalidshrt">Too Short</span></td>
</tr>
</table>
</form>
Here is how to create custom validation directive
angular.module('myApp',['ngMessages']);
angular.module('myApp',['ngMessages']).directive('customValidation',function(){
return{
restrict:'A',
require: 'ngModel',
link:function (scope, element, attr, ctrl) {// 4th argument contain model information
function validationError(value) // you can use any function and parameter name
{
if (value.length > 6) // if model length is greater then 6 it is valide state
{
ctrl.$setValidity('invalidshrt',true);
}
else
{
ctrl.$setValidity('invalidshrt',false) //if less then 6 is invalide
}
return value; //return to display error
}
ctrl.$parsers.push(validationError); //parsers change how view values will be saved in the model
}
};
});
$setValidity is inbuilt function to set model state to valid/invalid
I extended #Ben Lesh's answer with an ability to specify whether the validation is case sensitive or not (default)
use:
<input type="text" name="fruitName" ng-model="data.fruitName" blacklist="Coconuts,Bananas,Pears" caseSensitive="true" required/>
code:
angular.module('crm.directives', []).
directive('blacklist', [
function () {
return {
restrict: 'A',
require: 'ngModel',
scope: {
'blacklist': '=',
},
link: function ($scope, $elem, $attrs, modelCtrl) {
var check = function (value) {
if (!$attrs.casesensitive) {
value = (value && value.toUpperCase) ? value.toUpperCase() : value;
$scope.blacklist = _.map($scope.blacklist, function (item) {
return (item.toUpperCase) ? item.toUpperCase() : item
})
}
return !_.isArray($scope.blacklist) || $scope.blacklist.indexOf(value) === -1;
}
//For DOM -> model validation
modelCtrl.$parsers.unshift(function (value) {
var valid = check(value);
modelCtrl.$setValidity('blacklist', valid);
return value;
});
//For model -> DOM validation
modelCtrl.$formatters.unshift(function (value) {
modelCtrl.$setValidity('blacklist', check(value));
return value;
});
}
};
}
]);
Some great examples and libs presented in this thread, but they didn't quite have what I was looking for. My approach: angular-validity -- a promise based validation lib for asynchronous validation, with optional Bootstrap styling baked-in.
An angular-validity solution for the OP's use case might look something like this:
<input type="text" name="field4" ng-model="field4"
validity="eval"
validity-eval="!(field1 && field2 && field3 && !field4)"
validity-message-eval="This field is required">
Here's a Fiddle, if you want to take it for a spin. The lib is available on GitHub, has detailed documentation, and plenty of live demos.