angular - 格式化输入的电话号码成 Angular

Question

我已经看到了许多在Angularjs中格式化电话号码输入字段的解决方案，但是我在Angular 7上找不到任何东西。我真正想要的是用户在文本字段中键入以下内容:

123456789

并使文本字段将输入的格式设置为:

(123) 456-789

我该怎么做呢？我发现以下正则表达式可以对其进行验证:

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

Answer 1

您可以按照以下方法通过“电话屏蔽指令”进行处理，

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);
  }
}

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