Develop Reference

AngularJS dynamic required attribute in directive and form validation

I have a directive that receives whether an element should be required or not from a REST api. Right now, I can't seem to get the form to invalidate when an attribute is set to required.
So, in essence I'm able to dynamically add the 'required' attribute from the directive below, but it doesn't invalidate the form. Looking through chrome I see that, even though the required attribute exists, a required entry in the $error array doesn't exist.
app.directive('requireiftrue', function ($compile) {
return {
require: '?ngModel',
link: function (scope, el, attrs, ngModel) {
if (!ngModel) {
return;
}
if(attrs.requireiftrue==="true"){
console.log('should require');
el.attr('required', true);
$compile(el.contents())(scope);
}
else{
console.log('should not require');
}
}
};
});
Here's a jsfiddle to illustrate the problem. And, here's sample JSON returned from my rest API
{
race: false,
martialStatus: true,
}
EDIT: While the accepted answer got me up and running, I still had a good bit of finagling to do.
Namely:
1. Resolving a deferred promise to ensure that my form actually receives the required fields to validate
2. observing my 'requireiftrue' attribute
My solution
module config:
function config($stateProvider) {
$stateProvider
.state('testState', {
url: '/test/form',
controller: 'TestCtrl',
templateUrl: 'test/form/testForm.tpl.html',
resolve: {
formDefaultService: function getFormDefaults($q, dataservice) {
// Set up a promise to return
var deferred = $q.defer();
var myData = dataservice.getFormDefaults();
deferred.resolve(myData);
return deferred.promise;
//return
}
},
data: {
pageTitle: 'Test Info'
}
});
}
And, finally the directive / HTML that receives api data:
Directive:
.directive('requireiftrue', function ($compile) {
return {
require: '?ngModel',
link: function (scope, el, attrs, ngModel) {
if (!ngModel) {
return;
}
attrs.$observe('requireiftrue', function(value){
if(value==="true"){
el.attr('required', true);
el.removeAttr('requireiftrue');
$compile(el[0])(scope);
}
});
}
};
});
HTML:
<input max="40"
requireiftrue={{defaults.validation.name}}
validNumber
id="name"
name="name"
type="text"
ng-model="test.name"
class="form-control">

You had two issues:
The first is el.contents() returned an empty array. so The first thing you should do is change it to el[0]. But had el.contents() worked you would hav had a much more serious problem. You would have been trying to compile a directive that has itself as a directive which would lead to an infinite loop (well until the browser crashed any way).
So here is the revised code:
var app = angular.module('form-example', []);
app.directive('requireiftrue', function ($compile) {
return {
require: '?ngModel',
link: function (scope, el, attrs, ngModel) {
if (!ngModel) {
return;
}
if(attrs.requireiftrue==="true"){
console.log('should require');
el.attr('required', true);
el.removeAttr('requireiftrue');
$compile(el[0])(scope);
}
else{
console.log('should not require');
}
}
};
});
I should note however that now this directive is a one-off. If the model will change, the directive will not be on the element any longer to deal with it.

Instead of using a directive, use ng-init to initialize requireiftrue.
and assign this value to ng-required like ng-required="requireiftrue" as shown below. As you said you are getting the data from rest api, you can initialize requireiftrue with the value you are getting from api, instead of true or false as shown in example below.
Hope this helps you.
Updated fiddle
http://jsfiddle.net/zsrfe513/3/
<form ng-app="form-example" name='fo' class="row form-horizontal" novalidate>
<div class="control-group" ng-form="testReq">
<h3>Form invalid: {{testReq.$invalid}}</h3>
<label class="control-label" for="inputEmail">Email</label>
<div class="controls" ng-init='requireiftrue = true'>
<input id="inputEmail" placeholder="Email" ng-model="email" name='ip' ng-required='requireiftrue'>
<span ng-show="testReq.ip.$dirty && testReq.ip.$error.required">
Required.
</span>
</div>
</div>
</form>

Try:
1. adding the required directive to the input you want to apply validation to
<input id="inputEmail" class="requireiftrue" placeholder="Email"
ng-model="email" requireiftrue="true" required>
2 Defining the directive as type class and adding the directive class to the HTML input field
JS
app.directive('requireiftrue', function ($compile) {
return {
restrict: 'C',
require: '?ngModel',
.....
HTML
<input id="inputEmail" class="requireiftrue" placeholder="Email" ng-model="email" requireiftrue="true" required>
here is a update of your fiddle - http://jsfiddle.net/4fb6wg30/

You just need to add the "required" attribute to the input.
<input max="40"
requireiftrue={{defaults.validation.name}}
validNumber
id="name"
name="name"
type="text"
ng-model="test.name"
class="form-control"
required="required">

I used <input ng-required="true"> worked fine for my angular validation component.
If your using the new angular component make sure to pass in required: "#" instead of required: "="
scope: {
required: '#'
}
I also took this further and required integer and min/max validation the same way.

How to get min and max values of input angularjs

currently I'm using a custom directive which wraps the ng-minlength and ng-maxlength directives to apply the values of these directives to the model of the input. I need to do this because I'm creating a validation service which uses the angular $error object on a form to return a user friendly message about what's wrong. The problem is, when it comes to min and max lengths, I want to be able to tell the user what the length should be. I've got this working by using the following method
directive('minlength', ['$compile', function ($compile) {
return {
restrict: 'A',
require: 'ngModel',
compile: function compile(tElement) {
tElement.attr('ng-minlength', tElement.attr('minlength'));
tElement.removeAttr('minlength');
return {
post: function postLink(scope, elem, attrs) {
var keys,
form,
field = attrs['ngModel'];
$compile(elem)(scope);
for (keys in scope) {
if (scope.hasOwnProperty(keys)) {
if (keys.substring(0, 2).indexOf('$') < 0) {
if (keys !== 'this') {
form = keys;
break;
}
}
}
}
if (form) {
console.log(attrs);
scope[form][field]['minlength'] = attrs['minlength'];
}
}
}
}
}
}])
But this seems a bit longhanded and possibly difficult to maintain and test. Is there a better way to do this?

If you want just to inform the user about the min and the max:
var app = angular.module('myApp',[]);
app.controller('MyCtrl',function($scope){
$scope.minValue = 5;
$scope.maxValue = 10;
});
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>
<div ng-app="myApp">
<div ng-controller="MyCtrl">
<form name="myForm">
Last name: <input type="text" name="lastName" ng-model="user.last"
ng-minlength="{{minValue}}" ng-maxlength="{{maxValue}}">
<span class="error" ng-show="myForm.lastName.$error.minlength">
Should be {{minValue}} charachters long</span>
<span class="error" ng-show="myForm.lastName.$error.maxlength">
No more than {{maxValue}} characters please</span><br>
</form>
</div>
</div>

I want to be able to set Angulars ng-pattern inside a directive with a template and it's own scope to validate a form

This is part of a much more complicated directive that needs to have its own scope as well as require ngModel and replace the existing input. How can I have the directive add the ng-pattern attribute? As you can see in this jsfiddel the validation doesn't change based on the input if the ng-pattern is added in the template. This is because this will be added to an existing application that has a ton of different attributes already on a ton of different input elements, and I'm trying to make the addition as easy to implement as possible by just adding functionality to the existing input fields without messing up other things.
http://jsfiddle.net/MCq8V/
HTML
<div ng-app="demo" ng-init="" ng-controller="Demo">
<form name="myForm" ng-submit="onSubmit()">
<input lowercase type="text" ng-model="data" name="number">
Valid? {{myForm.number.$valid}}
<input type="submit" value="submit"/>
</form>
</div>
JS
var module = angular.module("demo", []);
module.directive('lowercase', function() {
return {
require: 'ngModel',
restrict: 'A',
scope:{},
replace: true,
link: function(scope, element, attr, ngModelCntrl) {
},
template: '<input class="something" ng-pattern="/^\d*$/">',
};
});
module.controller('Demo', Demo);
function Demo($scope) {
$scope.data = 'Some Value';
}
Thanks so much for any help! Ideally I would be able to just change something small and keep the ng-pattern, but I think I may have to do the validation setting on my own.

Here's how the pattern attribute is added to input item in a directive I have in my application. Note the use of compile at the end of the link function. In your case, rather than replace the element contents with a template, you'd just work with the existing element input tag.
link: function (scope, element, attrs, formController) {
// assigned template according to form field type
template = (scope.schema["enum"] !== undefined) &&
(scope.schema["enum"] !== null) ?
$templateCache.get("enumField.html") :
$templateCache.get("" + scope.schema.type + "Field.html");
element.html(template);
// update attributes - type, ng-required, ng-pattern, name
if (scope.schema.type === "number" || scope.schema.type === "integer") {
element.find("input").attr("type", "number");
}
element.find("input").attr("ng-required", scope.required);
if (scope.schema.pattern) {
element.find("input").attr("ng-pattern", "/" + scope.schema.pattern + "/");
}
element.find("input").attr("name", scope.field);
// compile template against current scope
return $compile(element.contents())(scope);
}

I tried quite a few things and it seemed that using a directive to replace an input with an input was tricking Angular up somewhere - so this is what I came up with:
http://jsfiddle.net/MCq8V/1/
HTML
<div ng-app="demo" ng-init="" ng-controller="Demo">
<form name="myForm" ng-submit="onSubmit()">
<div lowercase model="data"></div>
Valid? {{myForm.number.$valid}}
<input type="submit" value="submit"/>
</form>
</div>
JS
var module = angular.module("demo", []);
module.directive('lowercase', function() {
return {
restrict: 'A',
scope:{
data:'=model'
},
replace: true,
template: '<input class="something" ng-pattern="/^\\d*$/" name="number" ng-model="data" type="text">',
};
});
module.controller('Demo', Demo);
function Demo($scope) {
$scope.data = 'Some Value';
}
Also, you needed to escape your backslash in your regex with another backslash.

angular: Validate multiple dependent fields

Let's say I have the following (very simple) data structure:
$scope.accounts = [{
percent: 30,
name: "Checking"},
{ percent: 70,
name: "Savings"}];
Then I have the following structure as part of a form:
<div ng-repeat="account in accounts">
<input type="number" max="100" min="0" ng-model="account.percent" />
<input type="text" ng-model="account.name" />
</div>
Now, I want to validate that the percents sum to 100 for each set of accounts, but most of the examples I have seen of custom directives only deal with validating an individual value. What is an idiomatic way to create a directive that would validate multiple dependent fields at once? There are a fair amount of solutions for this in jquery, but I haven't been able to find a good source for Angular.
EDIT: I came up with the following custom directive ("share" is a synonym for the original code's "percent").
The share-validate directive takes a map of the form "{group: accounts, id: $index}" as its value.
app.directive('shareValidate', function() {
return {
restrict: 'A',
require: 'ngModel',
link: function(scope, elem, attr, ctrl) {
ctrl.$parsers.unshift(function(viewValue) {
params = angular.copy(scope.$eval(attr.shareValidate));
params.group.splice(params.id, 1);
var sum = +viewValue;
angular.forEach(params.group, function(entity, index) {
sum += +(entity.share);
});
ctrl.$setValidity('share', sum === 100);
return viewValue;
});
}
};
});
This ALMOST works, but can't handle the case in which a field is invalidated, but a subsequent change in another field makes it valid again. For example:
Field 1: 61
Field 2: 52
If I take Field 2 down to 39, Field 2 will now be valid, but Field 1 is still invalid. Ideas?

Ok, the following works (again, "share" is "percent"):
app.directive('shareValidate', function () {
return {
restrict: 'A',
require: 'ngModel',
link: function(scope, elem, attr, ctrl) {
scope.$watch(attr.shareValidate, function(newArr, oldArr) {
var sum = 0;
angular.forEach(newArr, function(entity, i) {
sum += entity.share;
});
if (sum === 100) {
ctrl.$setValidity('share', true);
scope.path.offers.invalidShares = false;
}
else {
ctrl.$setValidity('share', false);
scope.path.offers.invalidShares = true;
}
}, true); //enable deep dirty checking
}
};
});
In the HTML, set the attribute as "share-validate", and the value to the set of objects you want to watch.

You can check angularui library (ui-utility part). It has ui-validate directive.
One way you can implement it then is
<input type="number" name="accountNo" ng-model="account.percent"
ui-validate="{overflow : 'checkOverflow($value,account)' }">
On the controller create the method checkOverflow that return true or false based on account calculation.
I have not tried this myself but want to share the idea. Read the samples present on the site too.

I have a case where I have a dynamic form where I can have a variable number of input fields on my form and I needed to limit the number of input controls that are being added.
I couldn't easily restrict the adding of these input fields since they were generated by a combination of other factors, so I needed to invalidate the form if the number of input fields exceeded the limit. I did this by creating a reference to the form in my controller ctrl.myForm, and then each time the input controls are dynamically generated (in my controller code), I would do the limit check and then set the validity on the form like this: ctrl.myForm.$setValidity("maxCount", false);
This worked well since the validation wasn't determined by a specific input field, but the overall count of my inputs. This same approach could work if you have validation that needs to be done that is determined by the combination of multiple fields.

For my sanity
HTML
<form ng-submit="applyDefaultDays()" name="daysForm" ng-controller="DaysCtrl">
<div class="form-group">
<label for="startDate">Start Date</label>
<div class="input-group">
<input id="startDate"
ng-change="runAllValidators()"
ng-model="startDate"
type="text"
class="form-control"
name="startDate"
placeholder="mm/dd/yyyy"
ng-required
/>
</div>
</div>
<div class="form-group">
<label for="eEndDate">End Date</label>
<div class="input-group">
<input id="endDate"
ng-change="runAllValidators()"
ng-model="endDate"
type="text"
class="form-control"
name="endDate"
placeholder="mm/dd/yyyy"
ng-required
/>
</div>
</div>
<div class="text-right">
<button ng-disabled="daysForm.$invalid" type="submit" class="btn btn-default">Apply Default Dates</button>
</div>
JS
'use strict';
angular.module('myModule')
.controller('DaysCtrl', function($scope, $timeout) {
$scope.initDate = new Date();
$scope.startDate = angular.copy($scope.initDate);
$scope.endDate = angular.copy($scope.startDate);
$scope.endDate.setTime($scope.endDate.getTime() + 6*24*60*60*1000);
$scope.$watch("daysForm", function(){
//fields are only populated after controller is initialized
$timeout(function(){
//not all viewalues are set yet for somereason, timeout needed
$scope.daysForm.startDate.$validators.checkAgainst = function(){
$scope.daysForm.startDate.$setDirty();
return (new Date($scope.daysForm.startDate.$viewValue)).getTime() <=
(new Date($scope.daysForm.endDate.$viewValue)).getTime();
};
$scope.daysForm.endDate.$validators.checkAgainst = function(){
$scope.daysForm.endDate.$setDirty();
return (new Date($scope.daysForm.startDate.$viewValue)).getTime() <=
(new Date($scope.daysForm.endDate.$viewValue)).getTime();
};
});
});
$scope.runAllValidators = function(){
//need to run all validators on change
$scope.daysForm.startDate.$validate();
$scope.daysForm.endDate.$validate();
};
$scope.applyDefaultDays = function(){
//do stuff
}
});

You can define a single directive that is only responsible for this check.
<form>
<div ng-repeat="account in accounts">
<input type="number" max="100" min="0" ng-model="account.percent" />
<input type="text" ng-model="account.name" />
</div>
<!-- HERE IT IS -->
<sum-up-to-hundred accounts="accounts"></sum-up-to-hundred>
</form>
And here's the simple directive's code.
app.directive('sumUpToHundred', function() {
return {
scope: {
accounts: '<'
},
require: {
formCtrl: '^form'
},
bindToController: true,
controllerAs: '$ctrl',
controller: function() {
var vm = this;
vm.$doCheck = function(changes) {
var sum = vm.accounts.map((a)=> a.percent).reduce((total, n)=> total + n);
if (sum !== 100) {
vm.formCtrl.$setValidity('sumuptohundred', false);
} else {
vm.formCtrl.$setValidity('sumuptohundred', true);
}
};
}
};
});
Here's a plunker.

Angularjs initial form validation with directives

I have a validation directive called valid-number that is used to set the validity of a form using $setValidity - this works fine for any text values that I type into the input box that have the directive applied to as an attribute.
The HTML is
<form name="numberForm">
<input name="amount" type="text" ng-model="amount" required valid-number /></form>
The directive is as follow
angular.module('test',[]).directive('validNumber',function(){
return{
require: "ngModel",
link: function(scope, elm, attrs, ctrl){
var regex=/\d/;
ctrl.$parsers.unshift(function(viewValue){
var floatValue = parseFloat(viewValue);
if(regex.test(viewValue)){
ctrl.$setValidity('validNumber',true);
}
else{
ctrl.$setValidity('validNumber',false);
}
return viewValue;
});
}
};
});
However, I would also like the validation to be triggered and set the css to an invalid clsss if the value the input box is initialised to when the page is first loaded is invalid, eg if I set $scope.amount = 'not a number' I would expect the input box to have had the directive applied to it, but no joy. In order for not a number to be highlighted as invalid I have to make a change to the contents of the input, which triggers the directive.
How can I ensure the directive applies to whatever the <input> is initialised with?
A full code example is here;
http://jsfiddle.net/JW43C/5/

$parsers array contains a list of functions that will be applied to the value that model receives from the view (what user types in), and $formatters array contains the list of functions that are being applied to the model value before it's displayed in the view.
In your directive you correctly used the $parsers array, but you also need to add the $formatters array if you want the initial value to be validated:
angular.module('test',[]).directive('validNumber',function(){
return{
require: "ngModel",
link: function(scope, elm, attrs, ctrl){
var regex = /^\d$/;
var validator = function(value){
ctrl.$setValidity('validNumber', regex.test(value));
return value;
};
ctrl.$parsers.unshift(validator);
ctrl.$formatters.unshift(validator);
}
};
});
Demo plunker

You can simply call your verification function during the linking phase, like in this fiddle :
link: function(scope, elm, attrs, ctrl) {
var regex=/\d/;
var verificationFunction = function(viewValue) {
var floatValue = parseFloat(viewValue);
if(regex.test(viewValue)) {
ctrl.$setValidity('validNumber',true);
return viewValue;
}
else {
ctrl.$setValidity('validNumber',false);
return undefined;
}
};
ctrl.$parsers.unshift(verificationFunction);
verificationFunction();
}

After (>=) angular 1.3.1 version was released you could implement that behaviour with a little bit correct way, following angular validation directives style (e.g. required, maxlength).
In that case you have to append your validator as property of $validators array and there are no need in $parsers or $formatters anymore:
var app = angular.module('test', []);
app
.directive('validNumber', function() {
return {
require: "ngModel",
link: function(scope, elm, attrs, ctrl) {
var regex = /^\d+$/;
ctrl.$validators['validNumber'] = function(modelValue, viewValue) {
return regex.test(viewValue);
};
}
};
});
app.controller('NumberCtrl', NumberCtrl);
function NumberCtrl($scope) {
$scope.amount = '5z';
};
input.ng-invalid {
background-color: #FA787E;
}
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.3.1/angular.min.js"></script>
<div ng-app="test">
<div ng-controller="NumberCtrl">
<div ng-form name="numberForm">
<input name="amount"
type="text"
ng-model="amount"
required
valid-number />
<span ng-show="numberForm.amount.$error.validNumber">
Doesn't look like an integer
</span>
</div>
</div>
</div>