title: Angular 2 - accept only natural number in input
body: <p>I have a shop component and I need to disallow people to pick negative numbers in my input.</p>
  
  <p>For example, if user will type <strong>-3</strong> in my input, the input value will immadiately change to <strong>0</strong>.</p>
  
  <p>How I can control my angular 2 input <strong>OnChange</strong> value to set it back to <strong>0</strong> it the value is negative?</p>
  
  <p>Tried to use <code>(ngModelChange)="myMethod($event)"</code> and set the parameter to 0 if it's negative, but didn't work.</p>