node eventemitter emit a change event code example

Example 1: node js event emitter

const EventEmitter = require('events');

class MyEmitter extends EventEmitter {
  foo() {
    this.emit('test');
  }
}
const myEmitter = new MyEmitter();
myEmitter.on('test', () => console.log('Yay, it works!'));

myEmitter.foo();	// Yay it works!

Example 2: event module in node js

const myEmitter = new MyEmitter();
let m = 0;
myEmitter.on('event', () => {
  console.log(++m);
});
myEmitter.emit('event');
// Prints: 1
myEmitter.emit('event');
// Prints: 2