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

[Ethan Standel]

Do you realize that TypeScript fixes this much more elegantly by fronting all references to this with let _this = this;. I'm also much more pro-figuring-out-how-the-language-works rather than going down dependency he'll trying to patch it.

[JavaScript Joel]

TypeScript fixes some problems with this. Arrow functions fix some problems with this. These solutions do not fix ALL problems with this.

Consider this code that cannot be solved with TypeScript or arrow functions:

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

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

events.emit('button.click')

[Jim Przybylinski]

You fix it with an explicitly typed this.

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

events.on('button.*', function(this: EventEmitter2) {
  console.log('event:', this.event)
})

events.emit('button.click')