Emitter

Emitter is a Roblox Typescript package for creating event-emitting objects and classes.

npm install @rbxts/emitter

Usage

Creating Objects

To create an object, call the createEmitter function with the object you want to create the emitter out of, the type for the object, and the types for the events.

import { CreateEmitter } from "@rbxts/emitter";

interface Chef {
	Foods: string[];
}

interface ChefEvents {
	FoodCooked: (Food: string) => any;
}

const myChef = CreateEmitter<Chef, ChefEvents>({
	Foods: ["Pizza", "Macaroni", "Lasagna"]
});

Receiving Events

Events are connected to through a single method: Subscribe, with the first argument being the name of the event and the second argument being the callback.

myChef.Subscribe("FoodCooked", Food => {
	print(`Chef has cooked ${Food}!`);
});

Firing Events

Once again, triggering events goes through a single method: Fire, with the first argument being the name of the event and the following arguments being the parameters for that event.

while (true) {
	wait(1);
	const Food = MyChef.Foods[math.random(0, Foods.size - 1)];
	MyChef.Fire("FoodCooked", Food);
}

Unsubscribing from Events

To unsubscribe from an event, take the ID of the callback returned from the the Subscribe and pass it to the Unsubscribe method along with the name of the event you want to unsubscribe from.

const Subscription = MyChef.Subscribe("FoodCooked", print);
MyChef.Unsubscribe("FoodCooked", Subscription);

Creating Classes

Often times you'll want every instance of a custom class to have different events that can be connected to. For this, extend the Emitter class and pass in your event types.

Note: Keep in mind that the Fire method is private on classes, so you'll have to write wrapper methods to trigger events from the outside.

import { Emitter } from "@rbxts/emitter";

interface ChefEvents {
	FoodCooked: () => any;
}

class Chef extends Emitter<ChefEvents> {
	static Foods = ["Pizza", "Macaroni", "Lasagna"];
	
	public CookFood() {
		const Food = Chef.Foods[math.random(0, Chef.Foods.size - 1)];
		this.Fire("FoodCooked", Food);
	}
}

const MyChef = new Chef();
MyChef.Subscribe("FoodCooked", Food => {
	print(`This chef has just cooked ${Food}!`);
});

MyChef.CookFood();