Register listener to all events

[rahatarmanahmed]

I figure I could make another package myself or monkeypatch for my own needs, but I wanted to see if anyone was open to the idea of adding this to Emitter.

It would be nice if Emitter had a onAny method that worked the same as on, but listeners registered would be triggered when any event is emitted.

The only issue I can see with this is that listeners could not be called in the order they were subscribed (i.e., all onAny listeners will be invoked before the on listeners). I don't think Emitter makes any guarantees about callback order, but it's understandable if this is too much of a surprise for users of Emitter.

[rahatarmanahmed]

Oh, another issue I can think of is providing the event name to onAny listeners.

One solution is to make the callback signature for onAny listeners be (event, args...) ->. It's a bit inconsistent, though.

[maxbrunsfeld]

This seems like an unusual use case. Could you solve it using the existing Emitter API, just by calling emit multiple times?

class Person {
  onDidDoAnything (callback) {
    return this.emitter.on('did-anything', callback)
  }

  setName (name) {
    this.name = name
    this.emitter.emit('did-change-name', name)
    this.emitter.emit('did-anything')
  }

  setAge (age) {
    this.age = age
    this.emitter.emit('did-change-age', age)
    this.emitter.emit('did-anything')
  }
}

[rahatarmanahmed]

It is possible, but at that point I would just monkeypatch emit to trigger the did-anything event automatically to avoid having to manually do it every time I needed it. Adding .onAny only serves to avoid that monkeypatching.