AsyncValidatorFn • Angular
interface
stable
A function that receives a control and returns a Promise or observable that emits validation errors if present, otherwise null.
API
interface AsyncValidatorFn { (control: AbstractControl<any, any, any>): Promise<ValidationErrors | null> | Observable<ValidationErrors | null>;}
Promise<ValidationErrors | null> | Observable<ValidationErrors | null>@paramcontrolAbstractControl<any, any, any>
@returnsPromise<ValidationErrors | null> | Observable<ValidationErrors | null>