Allow setting up emitter

[Richienb]

Just like how Cold Observables set up their emitter when they are first subscribed to, something similar should be done here. Using Emittery.listenerAdded, it is possible to detect when events are first listened to so it should be easy to invoke a callback from there.

For example:

const Emittery = require('emittery');

const emitter = new Emittery();

emitter.setup('name', () => {
    // Prepare emitter...
});

// Invoke preparation logic
emitter.on('name', () => {
    //...
})

// @sindresorhus

[sindresorhus]

Do you actually need this for something? If so, what?

[Richienb]

This is useful for emitters that require network access for polling or have to subscribe to other event emitters. Here's my use case:

const Emittery = require("emittery")

const emitter = new Emittery()

emitter.setup("mouse", () => {
	terminal.grabInput({
		mouse: "button"
	})

	terminal.on("mouse", (name, data) => {
		// Handle data...

		emitter.emit("mouse", data)
	})
})

module.exports = emitter

[sindresorhus]

Alright. I think it needs a "unsetup" hook too then. And a better name than "setup". What naming do other similar packages use?

[Richienb]

@sindresorhus How about activate and deactivate?

[sindresorhus]

That's not better. I guess setup/teardown is fine. But how about init/deinit?

[Richienb]

But how about init/deinit

👍