class EventEmitt {
constructor () {
this.handlers = {}
}
on (eventName, cb) {
if (!this.handlers[eventName]) {
this.handlers[eventName] = []
}
this.handlers[eventName].push(cb)
}
emit (eventName, ...args) {
if (this.handlers[eventName]) {
this.handlers[eventName].forEach(callback => {
callback(...args)
})
}
}
}