so-52126279-input-ddau

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  actions: {
    updateVal(val) {
      val = parseInt(val);
      if (val >= 0) {
      	this.set('val', val);
      } else {
        window.alert('number must not be negative');
        this.notifyPropertyChange('val');
      }
    }
  },
  val: 0
});

templates.application.hbs

<h1>PoC for <a href="https://stackoverflow.com/questions/52126279/how-to-make-type-number-to-positive-numbers-only-using-ember-js">this questition</a> on StackOverflow</h1>

<p>
  Current value: {{val}}<br>
  Edit: <input type="number" value={{val}} onchange={{action "updateVal" value="target.value"}} min="0" >
</p>

twiddle.json

{
  "version": "0.15.0",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.js",
    "ember": "3.2.2",
    "ember-template-compiler": "3.2.2",
    "ember-testing": "3.2.2"
  },
  "addons": {
    "ember-data": "3.2.0"
  }
}