Node's Event Emitter and "bind" function

event-emitter.js

const { EventEmitter } = require('events');

const em = new EventEmitter();

function eventListener(response) {
  console.log(`Response Status: ${response.status}`);
}

function middleware(response) {
  em.on('finish', eventListener.bind(null, response));
  console.log('next()');
}

const response = { status: '200' };
middleware(response);

setTimeout(() => {
  em.emit('finish');
}, 1000);