How to Style Angular Reactive Forms: Highlighting Touched and Invalid Fields

Learn how to apply CSS styling to Angular reactive forms so that input fields only show as invalid after they have been touched by the user.
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Enhancing User Experience with Angular Reactive Forms Styling

When building forms in Angular, especially for sensitive tasks like changing a password, it's essential to provide clear and immediate feedback to users. One common requirement developers face is how to visually indicate when a form is invalid but only after the user has interacted with it. This keeps the user interface clean and avoids overwhelming users with error messages prematurely.

The Problem: Early Feedback on Validation

In your Angular app, you might have set up a reactive form for users to change their password. Using simple CSS, you may have initially added styling to indicate when an input is invalid like so:

[[See Video to Reveal this Text or Code Snippet]]

While this code works well to highlight invalid fields, it applies the red border before the user has even touched the input fields. This can lead to frustration and confusion as users may not have fully engaged with the form yet. So, the question arises: How can we ensure that error indicators only show after the form fields are touched?

The Solution: Using ng-touched Class

The good news is that Angular provides a straightforward solution with the ng-touched class. This class is applied to input fields when they have been interacted with by the user—providing a perfect indicator of when to show validation errors.

Updated CSS Styling

To only show the invalid border after a field has been touched, you can modify your CSS rule to utilize both the ng-touched and ng-invalid classes. Here’s how you can do it:

[[See Video to Reveal this Text or Code Snippet]]

How It Works

ng-touched: This class is automatically added by Angular when the user focuses on the input and then leaves it without filling it out.

ng-invalid: This class indicates that the current value of the form control is not valid based on the validation rules you've specified (like required fields, password strength, etc.).

When you use both of these classes together, the red border will only appear after a user has interacted with the input and it's still considered invalid. This creates a better user experience by ensuring that users are not overwhelmed by validation errors until they have had a chance to engage with the form.

Conclusion

Styling Angular reactive forms to show validation only after fields are touched is a key aspect of creating a user-friendly interface. By strategically using the ng-touched and ng-invalid classes, developers can help users identify errors at a suitable time, leading to a smoother experience when completing forms.

Now that you know how to implement this in your Angular application, you can enhance the user interaction of your forms while providing the necessary feedback at the right moments.

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