I have a function where TypeScript can infer the return type based on the type of the input parameters.

I’m working to create a Prisma extension. For reasons, I started with JavaScript, using JSDoc hints for typing. The extension actually works just fine; however, the type hints are terrible, which led me to believe I was doing something wrong. In fact, when I switched to a typescript transpiler, all sorts of errors appeared in my declaration files that were invisible when using esbuild. My biggest current challenge in squashing these is, I need to use a value provided by the user when the initial extension is instantiated as a key in various other type declarations in my declaration files.

I am a beginner in Typescript. I am trying to learn generics.

Say I want to extend the Promise class with an overriden then() method that does something before calling super.then():

I’m working on some type guards for an API framework and want to connect the path parameters (a string) to a validation object.

I have the following code (nb. this is a simplified version, there are more types allowed than just number or bigint, like time periods, etc.) :

Consider the following code:

I’m just playing around with TypeScript and wrote this:

A JavaScript Map object has the type Map<K, V>. I would like to create a type that matches V.

Here my generic function defc