fix: dont require index signature in event map typing

[forivall]

Without this change, the following error appears when using an interface
of event listeners:

Type 'MyEventListeners' does not satisfy the constraint 'ValidEventTypes'.
  Type 'MyEventListeners' is not assignable to type '{ [x: string]: any[] | ((...args: any[]) => void); }'.
    Index signature is missing in type 'NodeRunnerEventListeners<Output>

with an interface like

interface MyEventListeners {
  log(
    content: string,
    level?: 'error' | 'warn' | 'info' | 'debug' | 'silly'
  ): void;
}

[lpinca]

cc: @gfmio

[gfmio]

LGTM

I believe this is due to a recently introduced change in behaviour of theTypeScript type checker. Thanks for noticing and fixing!

[lpinca]

Thank you.

[RAnders00]

Maybe I'm doing it wrong but I still get the same error, even after upgrading to the new release

import EventEmitter from "eventemitter3";

interface MyEvents {
    example(param1: string, param2: number): void
}

export class Example extends EventEmitter<MyEvents> {

}

Playground Link

Type 'MyEvents' does not satisfy the constraint 'ValidEventTypes'. Type 'MyEvents' is not assignable to type '{ [x: string]: any[] | ((...args: any[]) => void) | undefined; }'. Index signature is missing in type 'MyEvents'.

[gfmio]

I've actually encountered the same issue this weekend. I had to relax the type constraints of ValidEventTypes a little bit, but the issue should be fixed once #232 has been merged.

@RAnders00 Feel free to test my branch with your code as well to be double check. I've also added a comment with a large code sample that shows the expected behaviour.

[forivall]

Yeah, i'm still on typescript 3.9.7 . I didn't check if it's an issue on typescript 4+

[forivall]

hmm, oddly, when i made the change to the index.d.ts directly, it worked, but now that i'm on the new version, it doesn't.

[gfmio]

@forivall Your and my version are virtually identical. I don't have a preference. I've verified that yours works as well.

[gfmio]

I'm also not sure what TypeScript version introduced the the issue. I tried out older TS versions, but they all seemed to fail, but I know that it did work at the time when we introduced the EventMap structure, because someone from the TypeScript team explicitly verified that it worked as well (for TypeScript 3.9).