help why bar any but not foo

11 Replies

chmodOP•2y ago

type AnyFunc = (...args: any[]) => any;
function proxy<T extends AnyFunc>(fn: T) {
   return fn;
}
const nowBarIsAny = proxy((foo: string, bar = 23) => {});
//      becomes  ^?          (foo: string, bar?: any) => void
//      instead should be    (foo: string, bar?: number) => void

type AnyFunc = (...args: any[]) => any;
function proxy<T extends AnyFunc>(fn: T) {
   return fn;
}
const nowBarIsAny = proxy((foo: string, bar = 23) => {});
//      becomes  ^?          (foo: string, bar?: any) => void
//      instead should be    (foo: string, bar?: number) => void

why does default bar become any, but foo works?

whatplan•2y ago

function proxy<T extends Function>(fn: T): T {
   return fn;
}
const nowBarIsAny = proxy((foo: string, bar = 23) => {});
//      ^?  (foo: string, bar?: number) => void

function proxy<T extends Function>(fn: T): T {
   return fn;
}
const nowBarIsAny = proxy((foo: string, bar = 23) => {});
//      ^?  (foo: string, bar?: number) => void

chmodOP•2y ago

thanks that worked! however now

function proxy<T extends AnyFunc>(fn: T) {
   type Params = Parameters<T>; // can't do this anymore
   return fn;
}

function proxy<T extends AnyFunc>(fn: T) {
   type Params = Parameters<T>; // can't do this anymore
   return fn;
}

fails with

 Type 'Function' is not assignable to type '(...args: any) => any'

 Type 'Function' is not assignable to type '(...args: any) => any'

whatplan•2y ago

hm yea this is weird

type MyFunction<T extends (...args: any[]) => any> = T extends (...args: infer A) => infer R
  ? (...args: A) => R
  : never;

function proxy<T extends (...args: any[]) => any>(fn: T): MyFunction<T> {
  return fn as unknown as MyFunction<T>;
}

const nowBarIsAny = proxy((foo: string, bar: number = 23) => {});

type MyFunction<T extends (...args: any[]) => any> = T extends (...args: infer A) => infer R
  ? (...args: A) => R
  : never;

function proxy<T extends (...args: any[]) => any>(fn: T): MyFunction<T> {
  return fn as unknown as MyFunction<T>;
}

const nowBarIsAny = proxy((foo: string, bar: number = 23) => {});

this is something but not probably the right solution

chmodOP•2y ago

oof still any really don't want to poison all references with generics but it seems it's inevitable

whatplan•2y ago

what is your use case?

chmodOP•2y ago

a mini trpc

type AnyFn<CTX = void> = CTX extends void ? (...args: any[]) => any : (ctx: CTX, ...args: any[]) => any;
type GenId<Fn extends AnyFn, CTX> = CTX extends void
   ? (...args: Parameters<Fn>) => string
   : OmitFirstArg<(...args: Parameters<Fn>) => string>;

type BaseRouter<CTX> = {
   [key: string]: BaseRouter<CTX> | AnyFn<CTX>;
};

type ReplaceAnyFnWithGenId<T, CTX> = {
   [K in keyof T]: T[K] extends AnyFn ? GenId<T[K], CTX> : T[K] extends BaseRouter<CTX> ? ReplaceAnyFnWithGenId<T[K], CTX> : never;
};

type AnyFn<CTX = void> = CTX extends void ? (...args: any[]) => any : (ctx: CTX, ...args: any[]) => any;
type GenId<Fn extends AnyFn, CTX> = CTX extends void
   ? (...args: Parameters<Fn>) => string
   : OmitFirstArg<(...args: Parameters<Fn>) => string>;

type BaseRouter<CTX> = {
   [key: string]: BaseRouter<CTX> | AnyFn<CTX>;
};

type ReplaceAnyFnWithGenId<T, CTX> = {
   [K in keyof T]: T[K] extends AnyFn ? GenId<T[K], CTX> : T[K] extends BaseRouter<CTX> ? ReplaceAnyFnWithGenId<T[K], CTX> : never;
};

seems impossible without having BaseRouter be a mapped type itself sorta like

type BaseRouter<T = AnyFn> = {
   [K in keyof T]: T[K] extends AnyFn
      ? T[K]
      : T[K] extends Record<string, any>
      ? BaseRouter<T[K]>
      : never;
};

type BaseRouter<T = AnyFn> = {
   [K in keyof T]: T[K] extends AnyFn
      ? T[K]
      : T[K] extends Record<string, any>
      ? BaseRouter<T[K]>
      : never;
};

whatplan•2y ago

ok gimme a sec to look through this Im out of ideas maybe someone it matts discord can help https://discord.gg/BT5NW6W4

chmodOP•2y ago

thanks for the efforts, I've been at this for several days (and yeah already there lol https://discord.com/channels/997886693233393714/1129809460966207558)

whatplan•2y ago

maybe take a look at the trpc repo might be helpful

chmodOP•2y ago

have it on the side too and it's pure sorcery too lol, but looks like mapping

type BaseRouter<CTX, T = AnyFn<CTX>> = {
   [K in keyof T]: BaseRouter<CTX> | AnyFn<CTX>;
};

type BaseRouter<CTX, T = AnyFn<CTX>> = {
   [K in keyof T]: BaseRouter<CTX> | AnyFn<CTX>;
};

~~annoyingly finally solved~~ nvm loses type enforcement for BaseRouter

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help why bar any but not foo