tiny-typed-emitter

Have your events and their listeners type-checked with no overhead.


Install

Simply add the dependency using npm:
``console
$ npm i tiny-typed-emitter
`
or using yarn:
`console
$ yarn add tiny-typed-emitter
`

Usage

1. import tiny-typed-emitter library:

`ts
import { TypedEmitter } from 'tiny-typed-emitter';
`

2. define events and their listener signatures (note: quotes around event names are not mandatory):
`ts
interface MyClassEvents {
'added': (el: string, wasNew: boolean) => void;
'deleted': (deletedCount: number) => void;
}
`

3. on this step depending on your use case, you can:
- define your custom class extending EventEmitter:
`ts
class MyClass extends TypedEmitter {
constructor() {
super();
}
}
`
- create new event emitter instance:
`ts
const emitter = new TypedEmitter();
`

Generic events interface

To use with generic events interface:

`ts
interface MyClassEvents {
'added': (el: T, wasNew: boolean) => void;
}

class MyClass extends TypedEmitter> {

}
`

Compatible subclasses with different events

The type of eventNames() is a superset of the actual event names to make
subclasses of a TypedEmitter that introduce different events type
compatible. For example the following is possible:

`ts
class Animal=ListenerSignature> extends TypedEmitter<{spawn: () => void} & E> {
constructor() {
super();
}
}

class Frog> extends Animal<{jump: () => void} & E> {
}

class Bird> extends Animal<{fly: () => void} & E> {
}

const animals: Animal[] = [new Frog(), new Bird()];
`

No Overhead


Library adds no overhead. All it does is it simply reexports renamed EventEmitter`
with customized typings.
You can check lib/index.js to see the exported code.