The Curious Case of Type Inference in TypeScript

Some time ago, I was working on a side project. It used one specific library with many events to listen to.

I wanted to use the same event kinds in my project so I do not reinvent the wheel.

The library creators buried them as the first parameter of an overloaded event listener function, like this:

type OverloadedFunction = {
    (event: 'eventA'): void;
}

I thought it would take less than mere seconds to import the proper type definitions and move on.