tsee's Introduction

tsee

Typed EventEmitter implemented with typed args, based on nodejs EventEmitter.
Fully implements NodeJS.EventEmitter type, provides interface & proxy class.

Check 'tseep'! Same api but world fastest event emitter

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).

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tsee's Issues

Is it possible to make a class inherit from this EventEmitter?

Just that. I do not see that specific usage in the README.

Missing EventEmitter API

For instance, the "newListener" event is not implemented. There are others.

Just wondering: is it really posible that those 90 lines do the same as those 647 lines?

"once" subscriptions broke other "on" subscription

In this example

import { EventEmitter } from './index';

const events = new EventEmitter<{
    foo: (a: number, b: string) => void,
}>();

events.once('foo', (a,b) => {
    console.log('ones listener foo', a,b)
})

events.on('foo', (a, b) => {
    console.log('default listener foo', a, b);
});

events.emit('foo', 1, 'first time');
events.emit('foo', 2, 'second time');

i expect to see logs like

ones listener foo 1 first time
default listener foo 1 first time
default listener foo 2 second time

but i see only

ones listener foo 1 first time
default listener foo 2 second time

I think problem in this line https://github.com/Morglod/tsee/blob/master/src/ee.ts#L17

because this.events modifides during call e in line https://github.com/Morglod/tsee/blob/master/src/ee.ts#L30

adding typed events to an extended class that extends EventEmitter?

hi, i'm creating a class that extends the Stream class, which extends EventEmitter. does this module support adding typed events to such classes?

interface MyEvents {
  'foo': () => void;
}

// how do I fit tsee here so that `MyClass` has the `foo` event?
class MyClass extends Stream {
  constructor() {
  }
}

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