Read only event emitter in Node

example.js

"use strict";

const ticker = require('./ticker');

ticker.on('tick', (tickCount) => console.log(tickCount, 'TICK'));
// ticker.emit('something', {}); <-- This will fail

roee.js

"use strict";

const EventEmitter = require('events');

module.exports = class Roee extends EventEmitter {
  constructor (executor) {
    super();
    var emit = this.emit.bind(this);
    this.emit = undefined;
    executor(emit);
  }
};

ticker.js

"use strict";

const Roee = require('./roee');

const ticker = new Roee((emit) => {
  let tickCount = 0;
  setInterval(() => emit('tick', tickCount++), 1000);
});

module.exports = ticker;