当文本框中恰好插入10位数字时，Ionic 2会调用函数

Question

I am new to ionic 2 / angular 2.
I want to display a operators select box exactly when the user complete the 10 digit mobile number input. Till now i have created a function in ts

showOperators()
{
    let len = this.mobileNo.length;
    if(len==10)
    {
        this.isOperator = True;
    }
    else
    {
        this.isOperator = False;
    }
} 

and calling this function as

<ion-input (keypress)="showOperators()" [(ngModel)]="mobileNo"></ion-input>  

and the div to display is

<div *ngIf="isOperator">
    <ion-select [(ngModel)]="operators">
      <ion-option value="1">Operator1</ion-option>
      <ion-option value="2">Operator2</ion-option>
    </ion-select>
</div>  

it shows the desired functionality. But i want to know is i am using the right way or is there any other good solution for this.

Answer 1

You can avoid having any code-behind by doing this:

  <ion-input  [(ngModel)]="mobileNo"></ion-input>  

  <div *ngIf="mobileNo?.length == 10">
    <ion-select>
      <ion-option value="1">Operator1</ion-option>
      <ion-option value="2">Operator2</ion-option>
    </ion-select>

Assuming less code means simplicity, this might be better.