Discussion on: Rethinking JavaScript: The complete elimination and eradication of JavaScript's this.

[JavaScript Joel]

Arrow functions solve ONE of the problems with this.

Here's a reference to this that you can't arrow function your way out of.

import { EventEmitter2 } from 'eventemitter2'
const events = new EventEmitter2({ wildcard: true })

events.on('button.*', function() {
  console.log('event:', this.event)
})

events.emit('button.click')

nothis also does more than remove this. It lets you use arrow functions and also argument destructuring. Both of which are not options otherwise.

[zeddotes]

What is the purpose of trying to access this.event on the 5th line? If this.event was a value declared in the parent scope, the fat arrow would actually save you. The implication of using EventEmitter2 would be so that you can access arguments from the callback of the events.on method (ie. args passed inside the callback).

[JavaScript Joel]

The code is correct. This is how their API is written. I need the this from the function inside the events.on method, not the parent scope.

It works the same way jQuery's this context works here:

$('p').on('click', function() {
  console.log($(this).text())
})

You can't write an arrow function for these.

[zeddotes]

Actually, jQuery calls the callback of the element's this passed into it via apply and call. Check it out: code.jquery.com/jquery-3.3.1.js

[benwick]

In jquerys events this is the same as event.delegateTarget: api.jquery.com/event.delegateTarget/

So you can use the arrow function to get access to the parent context and still access the element you have attached the listener to... Please don't stop using this just because you don't know how a lib works.

$('p').on('click', (evt) => {
  console.log($(evt.delegateTarget).text())
})