Скачать с ютуб Angular #67 - Reactive Form | Async Validator (How to use Async Validator in the Reactive Form) в хорошем качестве

Angular #67 - Reactive Form | Async Validator (How to use Async Validator in the Reactive Form)

Click to watch Angular Playlist:    • Angular   To view the code of this tutorial. Please visit this Github link: https://github.com/lets-build-with-co... Note : Switch the particular branch of the tutorials of Github To download my git repo of JSON Server & use it in you local for practice, Please visit this link: https://github.com/lets-build-with-co... Reactive Form in Angular - Async Validator In Angular, an asynchronous validator, also known as async validator, is a type of validator that performs validation checks asynchronously. It is used to validate form controls by executing an asynchronous operation, such as making an HTTP request or performing a time-consuming computation, to validate the form control's value. Async validators are useful when you need to perform validation tasks that involve asynchronous operations that may take some time to complete. Examples of scenarios where async validators can be used include checking if a username or email is already taken, validating a value against a server-side database, or performing complex validation logic that requires asynchronous computations. Async validators are created as functions that return a promise or an observable. The function is executed whenever the form control value changes, and the validation result is determined based on the resolved value of the promise or the emitted value of the observable.