tsee
Typed EventEmitter implemented with typed args, based on nodejs EventEmitter.
Fully implements NodeJS.EventEmitter type, provides interface & proxy class.
Install & use
npm i tsee
Simple usage:
import { EventEmitter } from 'tsee';
const events = new EventEmitter<{
foo: (a: number, b: string) => void,
}>();
// foo's arguments is fully type checked
events.emit('foo', 123, 'hello world');Cast any other compatible to NodeJS.EventEmitter to typed:
import { asTypedEventEmitter } from 'tsee';
const typedEmitter = asTypedEventEmitter<{
foo: (a: number, b: string) => void,
boo: (a: number, b: string) => void,
}>(myEmitter);
typedEmitter.emit('foo', 123, 'hello world');Advenced usage for non default event emitters
If you use custom EventEmitter implementation, you can simply cast it to tsee.IEventEmitter interface:
import { CustomEventEmitter } from 'my-event-emitter';
import * as tsee from 'tsee';
// Simple type case
const typed = new CustomEventEmitter() as any as tsee.IEventEmitter<{ ... }>;
// Functional cast with `NodeJS.EventEmitter` type constraints
const typed = asTypedEventEmitter<{ ... }>(new CustomEventEmitter());tsee.EventEmitter class is implemented EventEmitter from 'events' package.
Api
EventEmitter<T> where T extends { [eventName]: Call signature }.
EventEmitter.emit's args is fully typed based on events map.
For foo event in example above, signature is: emit(eventName: 'foo', a: number, b: string).