I have an account form, created by Angular Form and connected to a Firebase real-time database. In Angular, I write the following code
accountsForm: FormGroup = new FormGroup({
$key: new FormControl(null),
accountNo: new FormControl('', [Validators.required, Validators.maxLength(6), Validators.minLength(6)]),
});
The accountNo should be 'Required, 6 digits and Unique'. So In Angular, How can I do account No. unique?