Leveraging a tool to dynamically modify the styles of the active elements based on user interactions

Question

Leveraging a tool to dynamically modify the styles of the active elements based on user interactions

My goal is to enhance the flexibility of my service by enabling it to handle any input field dynamically. Currently, I find myself manually coding everything, which is becoming quite labor-intensive. Is there a way to pass the element object when the elements ng-change property is triggered? This way, I can update the elements ng-class accordingly.

Example HTML:

<input type="text" id="email" data-ng-model="email" data-ng-change="changeEmail()" placeholder="your email here" data-ng-class="emailFormControlColor">

In the controller:

$scope.changeEmail = function () {
    if ($checkInput.checkEmail($scope.email)) {
        // email input is valid
        $scope.emailFormControlColor = 'form-control-success'; // update class to success
    } else {
        // email input is invalid
        if ($scope.emailFormControlColor === 'form-control-success') 
            $scope.emailFormControlColor = 'form-control-error'; // update class to error
    }
};

The service (included in the controller arguments):

.service('checkInput', ['$controller', '$window', '$location', function ($controller, $window, $location) {
    return {
        checkEmail: function (email) {
            // <--- Here, I aim to update the ng-class of the focused element dynamically! This would eliminate the need for manual coding for each input field!
            var regex = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
            return regex.test(email);
        }
    };
}])

Currently, I am manually updating the $scope.emailFormControlColor. But what if I have multiple input fields:

<input type="text" id="email1" data-ng-model="email1" data-ng-change="changeEmail()" placeholder="your email here" data-ng-class="emailFormControlColor1">
<input type="text" id="email2" data-ng-model="email2" data-ng-change="changeEmail()" placeholder="your email here" data-ng-class="emailFormControlColor2">
<input type="text" id="email3" data-ng-model="email3" data-ng-change="changeEmail()" placeholder="your email here" data-ng-class="emailFormControlColor3">

How can I modify my service to eliminate the need for manual coding like:

$scope.emailFormControlColor1 = 'form-control-success';
$scope.emailFormControlColor2 = 'form-control-success';
$scope.emailFormControlColor3 = 'form-control-success';

I hope my query is clear. If not, please let me know and I will clarify!

javascript angularjs

Answer 1

Answer №1

In my opinion, utilizing a directive to address this issue is the preferred approach. Firstly, it is generally discouraged to manipulate the DOM directly within a controller or service as it is considered an anti-pattern.

Another benefit of using a directive is that it provides access to the DOM element on which the directive is applied. Below is a snippet of untested code that can serve as a starting point:

myApp.directive('validateEmail', function() {
  require: 'ngModel',
  link: function(scope, element, attributes, ngModelController) {
    // Ensure ng-model is used on this element to interact with Angular's validator pipeline
    ngModelController.validators.validateEmail = function(modelValue, viewValue) {
      // Determine if the email is valid based on a regular expression
      var regex = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
      var isValid = regex.test(viewValue);
      // Utilize this opportunity to manipulate the DOM
      element.toggleClass('valid-email', isValid);
      element.toggleClass('invalid-email', !isValid);
      return isValid;
    });
  }
});

Instead of directly adding CSS classes in the directive, you can leverage Angular's built-in validation feature. The directive remains the same, but the CSS classes are not applied within the directive. When the directive's validation logic returns false, Angular automatically marks the field as invalid, allowing you to style it in your HTML:

<form name="myForm">
  <input ng-model="userEmail"
         name="email" 
         validate-email
         ng-class="{'valid-email': myForm.email.$valid, 'invalid-email': myForm.email.$invalid}">
</form>

In the above code, the CSS classes are applied when the field is invalid. You can also target specific validation errors by referencing the validator name. For example:

<form name="myForm">
  <input ng-model="userEmail"
         name="email" 
         validate-email
         ng-class="{'valid-email': !myForm.email.$error.validateEmail, 'invalid-email': myForm.email.$error.validateEmail}">
</form>

Answer 2

In my opinion, utilizing a directive to address this issue is the preferred approach. Firstly, it is generally discouraged to manipulate the DOM directly within a controller or service as it is considered an anti-pattern.

Another benefit of using a directive is that it provides access to the DOM element on which the directive is applied. Below is a snippet of untested code that can serve as a starting point:

myApp.directive('validateEmail', function() {
  require: 'ngModel',
  link: function(scope, element, attributes, ngModelController) {
    // Ensure ng-model is used on this element to interact with Angular's validator pipeline
    ngModelController.validators.validateEmail = function(modelValue, viewValue) {
      // Determine if the email is valid based on a regular expression
      var regex = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
      var isValid = regex.test(viewValue);
      // Utilize this opportunity to manipulate the DOM
      element.toggleClass('valid-email', isValid);
      element.toggleClass('invalid-email', !isValid);
      return isValid;
    });
  }
});

Instead of directly adding CSS classes in the directive, you can leverage Angular's built-in validation feature. The directive remains the same, but the CSS classes are not applied within the directive. When the directive's validation logic returns false, Angular automatically marks the field as invalid, allowing you to style it in your HTML:

<form name="myForm">
  <input ng-model="userEmail"
         name="email" 
         validate-email
         ng-class="{'valid-email': myForm.email.$valid, 'invalid-email': myForm.email.$invalid}">
</form>

In the above code, the CSS classes are applied when the field is invalid. You can also target specific validation errors by referencing the validator name. For example:

<form name="myForm">
  <input ng-model="userEmail"
         name="email" 
         validate-email
         ng-class="{'valid-email': !myForm.email.$error.validateEmail, 'invalid-email': myForm.email.$error.validateEmail}">
</form>

Answer 3

Answer №2

To streamline the process, I suggest creating an object that consolidates all the necessary email information. Here's an example:

HTML:

<input type="text" id="email0" data-ng-model="emails[0].value" data-ng-change="changeEmail(emails[0])" placeholder="your email here" data-ng-class="emails[0].class">
<input type="text" id="email1" data-ng-model="emails[1].value" data-ng-change="changeEmail(emails[1])" placeholder="your email here" data-ng-class="emails[1].class">
<input type="text" id="email2" data-ng-model="emails[2].value" data-ng-change="changeEmail(emails[2])" placeholder="your email here" data-ng-class="emails[2].class">

JavaScript:

$scope.emails = [
    { value: '', class: '' },
    { value: '', class: '' },
    { value: '', class: '' },
];

$scope.changeEmail = function (email) {
    if ($checkInput.checkEmail(email)) {
        // email input is good
        email.class = 'form-control-success'; // change from error to success
    } else {
        // email input is bad
        if (email.class === 'form-control-success') {
            email.class = 'form-control-error'; // change from success to error
        }
    }
};

To avoid repetition in the HTML, consider using ng-repeat as a more efficient approach.

Answer 4

To streamline the process, I suggest creating an object that consolidates all the necessary email information. Here's an example:

HTML:

<input type="text" id="email0" data-ng-model="emails[0].value" data-ng-change="changeEmail(emails[0])" placeholder="your email here" data-ng-class="emails[0].class">
<input type="text" id="email1" data-ng-model="emails[1].value" data-ng-change="changeEmail(emails[1])" placeholder="your email here" data-ng-class="emails[1].class">
<input type="text" id="email2" data-ng-model="emails[2].value" data-ng-change="changeEmail(emails[2])" placeholder="your email here" data-ng-class="emails[2].class">

JavaScript:

$scope.emails = [
    { value: '', class: '' },
    { value: '', class: '' },
    { value: '', class: '' },
];

$scope.changeEmail = function (email) {
    if ($checkInput.checkEmail(email)) {
        // email input is good
        email.class = 'form-control-success'; // change from error to success
    } else {
        // email input is bad
        if (email.class === 'form-control-success') {
            email.class = 'form-control-error'; // change from success to error
        }
    }
};

To avoid repetition in the HTML, consider using ng-repeat as a more efficient approach.

Answer 5

Answer №3

Although Sunil D. led me in the right direction, the code he provided was not correct. Below is the corrected code that successfully makes it work. http://codepen.io/basickarl/pen/MyoZNC

HTML:

<div ng-app="app" ng-controller="ctrl">
  <form name="myForm">
    <input ng-model="name" name="name">
    <input ng-model="email" name="email" check-email>
  </form>
</div>

CSS:

input {
  border: 5px;
  border-style: solid;
  border-color: silver;
}
.input-invalid {
  border-color: red;
}
.input-valid {
  border-color: lime;
}

JS:

var app = angular.module('app', []);
app.controller('ctrl', ['$scope', function($scope) {
  $scope.name = "";
  $scope.email = "";
}]);
app.directive('checkEmail', [function() {
  return {
    restrict: 'A',
    require: 'ngModel',
    link: function(scope, el, attr, ctrl) {
      ctrl.$validators.checkEmail = function(modelVal, viewVal) {
        var regex = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
        var isValid = regex.test(viewVal);
        el.toggleClass('input-valid', isValid);
        el.toggleClass('input-invalid', !isValid);
        return isValid;
      }
    }
  }
}]);

Answer 6

Although Sunil D. led me in the right direction, the code he provided was not correct. Below is the corrected code that successfully makes it work. http://codepen.io/basickarl/pen/MyoZNC

HTML:

<div ng-app="app" ng-controller="ctrl">
  <form name="myForm">
    <input ng-model="name" name="name">
    <input ng-model="email" name="email" check-email>
  </form>
</div>

CSS:

input {
  border: 5px;
  border-style: solid;
  border-color: silver;
}
.input-invalid {
  border-color: red;
}
.input-valid {
  border-color: lime;
}

JS:

var app = angular.module('app', []);
app.controller('ctrl', ['$scope', function($scope) {
  $scope.name = "";
  $scope.email = "";
}]);
app.directive('checkEmail', [function() {
  return {
    restrict: 'A',
    require: 'ngModel',
    link: function(scope, el, attr, ctrl) {
      ctrl.$validators.checkEmail = function(modelVal, viewVal) {
        var regex = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
        var isValid = regex.test(viewVal);
        el.toggleClass('input-valid', isValid);
        el.toggleClass('input-invalid', !isValid);
        return isValid;
      }
    }
  }
}]);

Leveraging a tool to dynamically modify the styles of the active elements based on user interactions

Answer №1

Answer №2

Answer №3

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