30-seconds-of-code: Potential memory leak in createEventHub

[GrosSacASac]

Bug description

https://github.com/30-seconds/30-seconds-of-code#createeventhub-

on creates an array, off never removes it

Steps to reproduce

Run this code

const createEventHub = () => ({
  hub: Object.create(null),
  emit(event, data) {
    (this.hub[event] || []).forEach(handler => handler(data));
  },
  on(event, handler) {
    if (!this.hub[event]) this.hub[event] = [];
    this.hub[event].push(handler);
  },
  off(event, handler) {
    const i = (this.hub[event] || []).findIndex(h => h === handler);
    if (i > -1) this.hub[event].splice(i, 1);
  }
});

const ee = createEventHub();
let evolvingEventName = 0;
setInterval(() => {
    const eventName = String(evolvingEventName);
    ee.on(eventName, Number);
    ee.off(eventName, Number);
    evolvingEventName++;
}, 1);

setInterval(() => {
    console.log(`Number of arrays keeps growing ${Object.keys(ee.hub).length}`);
}, 1000);

Expected behavior

Expected to see the number 0

Example where it is solved

https://github.com/GrosSacASac/event-e3/blob/master/EventEmitter3.mjs#L81

[skatcat31]

This would be a great PR!

[vmarchesin]

I apologize for the messy history. Everything should be in order now. It's my first time contributing here, I'll be more careful next time.

[lock[bot]]

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