Formatting Phone Number Input In Angular

问题

I have seen many solutions to formatting a phone number input field in Angularjs, but I cannot find anything on Angular 7. What I essentially want is for the user to type the following in the textfield:

123456789

and for the textfield to format the input as:

(123) 456-789

how can I go about doing this? I have found the following regex to validate it:

^(\([0-9]{3}\) |[0-9]{3}-)[0-9]{3}-[0-9]{4}$

回答1:

You can handle this with a Phone Mask Directive as follows,

export class PhoneMaskDirective {

  constructor(public ngControl: NgControl) { }

  @HostListener('ngModelChange', ['$event'])
  onModelChange(event) {
    this.onInputChange(event, false);
  }

  @HostListener('keydown.backspace', ['$event'])
  keydownBackspace(event) {
    this.onInputChange(event.target.value, true);
  }


  onInputChange(event, backspace) {
    let newVal = event.replace(/\D/g, '');
    if (backspace && newVal.length <= 6) {
      newVal = newVal.substring(0, newVal.length - 1);
    }
    if (newVal.length === 0) {
      newVal = '';
    } else if (newVal.length <= 3) {
      newVal = newVal.replace(/^(\d{0,3})/, '($1)');
    } else if (newVal.length <= 6) {
      newVal = newVal.replace(/^(\d{0,3})(\d{0,3})/, '($1) $2');
    } else if (newVal.length <= 10) {
      newVal = newVal.replace(/^(\d{0,3})(\d{0,3})(\d{0,4})/, '($1) $2-$3');
    } else {
      newVal = newVal.substring(0, 10);
      newVal = newVal.replace(/^(\d{0,3})(\d{0,3})(\d{0,4})/, '($1) $2-$3');
    }
    this.ngControl.valueAccessor.writeValue(newVal);
  }
}

STACKBLITZ DEMO

来源：https://stackoverflow.com/questions/58469413/formatting-phone-number-input-in-angular