How to Implement Angular Material Time Input Validation in Reactive Forms

Learn how to validate time inputs in Angular Material Reactive Forms, ensuring the inputs respect a specific hour range while providing dynamic feedback to users.
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Implementing Angular Material Time Input Validation in Reactive Forms

When building forms in Angular, particularly using Angular Material with Reactive Forms, it's crucial to ensure that the user inputs meet specific criteria. One common scenario is when you need to validate time inputs within a defined range. In this guide, we'll explore how to set up a Reactive Form with time input validation that ensures the user input is between 09:00 and 13:00.

The Problem Statement

Let’s say you have two time input fields, Min Hour and Max Hour, and you want to ensure that:

The minimum hour cannot be less than 09:00.

The maximum hour cannot exceed 13:00.

The minimum hour must always be less than the maximum hour.

To achieve this, we will create custom validation logic that will provide real-time feedback to the user as they fill out the form.

Setting Up the Reactive Form

Firstly, you need to create your form structure in your Angular component. This example assumes you're using Angular 17 with Angular Material:

HTML Structure

Here’s how the template for your time input looks like:

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

TypeScript Logic

Next, we’ll implement the logic for validating these inputs in the component.

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

Explanation of the Code

Form Group Initialization: We create a reactive form group with validators for the min and max time.

Custom Validator Function: The _minTimeValidator function checks if the input time is greater than or equal to 09:00.

Dynamic Validation: We subscribe to valueChanges on the form group to dynamically check if the minHour is always less than the maxHour.

Clean-Up: On component destroy, we unsubscribe from the observable to prevent memory leaks.

Conclusion

By following the outlined steps, you can successfully implement Angular Material Time Input Validation in a Reactive Form. This not only enhances user experience with real-time feedback but also ensures data integrity across your application.

If you encounter issues or have further questions, feel free to reach out!