tiny-typed-emitter
Have your events and their listeners type-checked with no overhead.Install
Simply add the dependency using npm:$ npm i tiny-typed-emitter
or using yarn:
$ yarn add tiny-typed-emitter
Usage
- import tiny-typed-emitter library:
```ts import { TypedEmitter } from 'tiny-typed-emitter'; ```
- define events and their listener signatures (note: quotes around event names are not mandatory):
'added': (el: string, wasNew: boolean) => void;
'deleted': (deletedCount: number) => void;
}
```- on this step depending on your use case, you can:
EventEmitter
:```ts
class MyClass extends TypedEmitter<MyClassEvents> {
constructor() {
super();
}
}
```
- create new event emitter instance:```ts
const emitter = new TypedEmitter<MyClassEvent>();
```
Generic events interface
To use with generic events interface:interface MyClassEvents<T> {
'added': (el: T, wasNew: boolean) => void;
}
class MyClass<T> extends TypedEmitter<MyClassEvents<T>> {
}
Compatible subclasses with different events
The type ofeventNames()
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:class Animal<E extends ListenerSignature<E>=ListenerSignature<unknown>> extends TypedEmitter<{spawn: () => void} & E> {
constructor() {
super();
}
}
class Frog<E extends ListenerSignature<E>> extends Animal<{jump: () => void} & E> {
}
class Bird<E extends ListenerSignature<E>> 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 renamedEventEmitter
with customized typings.
You can check lib/index.js to see the exported code.