ticker event emitter factory

ticker.js

/**
 * Write a function that accepts a number an a callback as the arguments. The function will return an EventEmitter 
 * that emits an event called 'tick' every 50 milliseconds until the number of milliseconds is passed from the invocation
 * of the function. The function will also call the callback when the number of milliseconds has passed, providing, as 
 * the result, the total count of tick events emitted. Hint: you can use setTimeout() to schedule another setTimeout()
 * recursively.
 */
module.exports = function ticker(number, cb) {
    const ee = new (require('events').EventEmitter)()
    let count = 0
    ee.on('tick', function(time) {
        if (time > number) return cb(null, count)
        setTimeout(function() {
            ee.emit('tick', time + 50)
            count++
        }, 50)
    })
    process.nextTick(ee.emit.bind(ee, 'tick', 0))
    return ee
}