Every time the value of a form control changes, Angular runs validation and generates either a list of validation errors that results in an INVALID status, or null, which results in a VALID status.

For example, if one of the controls in a group is invalid, the entire group becomes invalid. FormGroup is one of the four fundamental building blocks used to define forms in Angular, along with FormControl, …

For example, if one of the controls in a FormArray is invalid, the entire array becomes invalid. FormArray accepts one generic argument, which is the type of the controls inside.

This is the archived documentation for Angular v17. Please visit angular.dev to see this page for the current version of Angular.

The ng-valid / ng-invalid pair is particularly interesting, because you want to send a strong visual signal when the values are invalid. You also want to mark required fields.

By default, these error messages are shown when the control is invalid and either the user has interacted with (touched) the element or the parent form has been submitted.

Sep 26, 2023 · Angular previously supported an integration with the Web Tracing Framework (WTF) for performance testing of Angular applications. This integration has not been maintained and is now …

This is the archived documentation for Angular v17. Please visit angular.dev to see this page for the current version of Angular.

Angular applications are styled with standard CSS. That means you can apply everything you know about CSS stylesheets, selectors, rules, and media queries directly to Angular applications.

This is one of the four fundamental building blocks of Angular forms, along with FormGroup, FormArray and FormRecord. It extends the AbstractControl class that implements most of the base functionality …