Typescript named curry functino

named-curry.ts

type Tequal<A, B> = A extends B ? (B extends A ? true : false) : false;

type Bind<P extends Record<string, any>, R> = Tequal<P, {}> extends false
  ? (<K extends keyof P>(
      key: K,
      value: P[K]
    ) => Bind<Pick<P, Exclude<keyof P, K>>, R>)
  : () => R;

function curryNamed<Params extends Record<string, any>, R>(
  fun: (p: Params) => R
): Bind<Params, R> {
  const params: Partial<Params> = {};
  const bind = (key: any, value: any) => {
    if (!key) {
      return fun(params as Required<Params>);
    }
    params[key] = value;
    return bind;
  };
  return bind as any;
}

const a = curryNamed((p: { a: number; b: Date; c: string }) => {
  return "it works" as const;
});

const b = a("a", 45)("c", "hello")("b", new Date())();