Directive.ts

/**
 * @author Rodinei Fagundes <rodinei.jf@gmail.com>
 */


import { Directive, HostListener, Input } from '@angular/core';
import { NgControl } from '@angular/forms';

@Directive({
  selector: '[custom-directive]' // Attribute selector
})
export class CustomDirective {

  @Input('textMask')
  textMaskConfig = {
    mask: []
  };

  constructor(private ngControl: NgControl) { }

  @HostListener('blur', ['$event'])
  onBlur($event: any) {

    let value = this.ngControl.value;
    // Workaround for https://github.com/text-mask/text-mask/issues/294
    if (value.length > this.textMaskConfig.mask.length) {
      value = value.slice(0, -1);
    }
    
    this.ngControl.control.setValue(value);
  }

}