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Have your events and their listeners type-checked withno overhead.

Simply add the dependency usingnpm:

$npm i tiny-typed-emitter

or usingyarn:

$yarn add tiny-typed-emitter

1. importtiny-typed-emitter library:

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

2. define events and their listener signatures (note: quotes around event names are not mandatory):

interfaceMyClassEvents{'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 extendingEventEmitter:

  classMyClassextendsTypedEmitter<MyClassEvents>{constructor(){super();}}

• create new event emitter instance:

  constemitter=newTypedEmitter<MyClassEvent>();

To use with generic events interface:

interfaceMyClassEvents<T>{'added':(el:T,wasNew:boolean)=>void;}classMyClass<T>extendsTypedEmitter<MyClassEvents<T>>{}

The type ofeventNames() is a superset of the actual event names to makesubclasses of aTypedEmitter that introduce different events typecompatible. For example the following is possible:

classAnimal<EextendsListenerSignature<E>=ListenerSignature<unknown>>extendsTypedEmitter<{spawn:()=>void}&E>{constructor(){super();}}classFrog<EextendsListenerSignature<E>>extendsAnimal<{jump:()=>void}&E>{}classBird<EextendsListenerSignature<E>>extendsAnimal<{fly:()=>void}&E>{}constanimals:Animal[]=[newFrog(),newBird()];

Library adds no overhead. All it does is it simply reexports renamedEventEmitterwith customized typings.You can checklib/index.js to see the exported code.