is event emitter baked in to all objects?

[espruino-discuss]

Posted at 2020-09-03 by dgk

In node/browser if I need to incorporate an event emitter I either use the native events module or third party. Typically I'd create a new class by extending the event emitter. Like so. https://nodejs.org/api/events.html

import EventEmitter from 'events'
class SomeClass extends EventEmitter {
  constructor() {
  }
}

but it seems that all (plain?) objects in Espruino have an event emitter baked in by default. https://www.espruino.com/Reference#l_Object_emit

So when I make a new class or make an object like so I get an event emitter as well?

Is the actual event emitter module available? If so where is that in the api docs

const obj = {}

class SomeClass {
  constructor() {
  }
}

const cls = new SomeClass()
obj.on('test',  val => { console.log(val) })
cls.on('test',  val => { console.log(val) })
cls.emit('test','class')
obj.emit('test','object')

[gfwilliams]

Posted at 2020-09-04 by @gfwilliams

Yes, that's right. There's no explicit EventEmitter class. At the moment it is in all objects by default - initially the performance cost of adding it to every object was less than having two different kinds of object. It's something I did plan on changing at some point but it's been low priority.