inputWithHandle

controllers.application\.js

import Controller from '@ember/controller';
import { tracked } from '@glimmer/tracking';
import { action } from '@ember/object';

export default class ApplicationController extends Controller {
  appName = 'Input with handler example';
  @tracked text;

 handleInput(event) {
  event.preventDefault();
  let value = event.target.value;
  let text = value.split('').filter((char)=>/[0-9]/.test(char)).join('');
  
   if (text !== value) {
   	 event.target.value = text;
   }
  
   this.text = text;
} 
}

templates.application\.hbs

<h1>{{this.appName}}</h1>
<br>
<br>
<input
  value={{this.text}}
  {{on "input" this.handleInput}}
>
<br>
<br>

twiddle\.json

{
  "version": "0.17.1",
  "EmberENV": {
    "FEATURES": {},
    "_TEMPLATE_ONLY_GLIMMER_COMPONENTS": false,
    "_APPLICATION_TEMPLATE_WRAPPER": true,
    "_JQUERY_INTEGRATION": true
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.5.1/jquery.js",
    "ember": "3.18.1",
    "ember-template-compiler": "3.18.1",
    "ember-testing": "3.18.1"
  },
  "addons": {
    "@glimmer/component": "1.0.0"
  }
}