mat input mask is not allowing alphanumeric for the input field. Below is my code. Am I missing something? I tried to have keypress event but still it is not allowing alphanumeric. Any suggestion please to change below code to allow alphanumeric in below format.

I have to mask it to this format( ###-##-##),Ex: DS9-1-B-1

<input matInput  mask="000-0-0-0" (keypress)="keyPressAlphaNumeric($event)" required>


  keyPressAlphaNumeric(event) {

    var inp = String.fromCharCode(event.keyCode);

    if (/[a-zA-Z0-9]/.test(inp)) {
      return true;
    } else {
      event.preventDefault();
      return false;
    }
  }