[feat] more accurate type for just-curry-it

Description

type MP2 = {
  a1: "a2";
  b1: "b2";
};
type MP3 = {
  a1: "a3";
  b1: "b3";
};
type MR = {
  a1: "ar";
  b1: "br";
};
function foo<K extends keyof MP2>(p1: K, p2: MP2[K], p3: MP3[K]): MR[K] {
  return { p1, p2, p3 } as any;
}

// no errror
curry(foo)('a1')('b2')

// "ar" | "br"
const r = curry(foo)('a1')('a2')('a3')
void r

// @ts-expect-error
curry(foo)('a1')('b2')

// "ar"
const r = curry(foo)('a1')('a2')('a3')
void r

Contributor guide

Tech stack

typescript

Domain

developer experience

Issue type

feature

DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.

3

Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.

1-3 hours

Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.

stale

ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.

clear

Prerequisites

TypeScript genericsconditional typescurrying

Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.

30

Research direction

Investigate the current type definitions of just curry it in the repository. Refer to the related TypeScript issue (microsoft/TypeScript#50991) for discussion on possible implementations. Implement overloaded type definitions that preserve the correlation between argument types and return type, using mapped types and key remapping. Ensure the solution matches the expected behavior shown in the issue description.