EDIT

Apparently there is a better way to do this however I didn’t fully understand what was going on in the end, so am currently sticking with the following approach.

I was recently working on a project that leveraged the event-emitter pattern. The project used the implementation given by npm events which basically implements the nodejs event-emitter in all its glory in vanilla javascript for everyone to use.

I do like the event emitter, but I also like using Typescript and getting type-safety. I naturally went to use the npm @types/events package to get the typings, but it doesn’t give type-safety around the types of events that you are using. So I made my own declaration which gives this ability. This has likely been done already, but I just put it in a gist for using later:

It handles type safety by using the keyof directive offered by the Typescript Compiler.

Using it is simple:

export default interface MyEvents {
    "stateChanged": {state:any,isChanged:boolean};
    "remoteDisconnected": void;
    "remoteConnected": void;
}

export interface MyEventEmitter extends TypedEventEmitter<MyEvents>{

}

// You'll actually have to create a class that inherits from 
// EventEmitter at some point and cast it to a MyEventEmitter

Then when your using your event emitter in code, you’ll get intellisense. Here’s an example from the project I’m currently working on:

Pleasant coding.