miyaokamarina

type DeepReadonly<T> =
  T extends [infer A]                                                       ? DeepReadonlyObject<[A]> :
  T extends [infer A, infer B]                                              ? DeepReadonlyObject<[A, B]> :
  T extends [infer A, infer B, infer C]                                     ? DeepReadonlyObject<[A, B, C]> :
  T extends [infer A, infer B, infer C, infer D]                            ? DeepReadonlyObject<[A, B, C, D]> :
  T extends [infer A, infer B, infer C, infer D, infer E]                   ? DeepReadonlyObject<[A, B, C, D, E]> :
  T extends [infer A, infer B, infer C, infer D, infer E, infer F]          ? DeepReadonlyObject<[A, B, C, D, E, F]> :
  T extends [infer A, infer B, infer C, infer D, infer E, infer F, infer G] ? DeepReadonlyObject<[A, B, C, D, E, F, G]> :
  T extends (infer A)[]           ? DeepReadonlyArray<A> :
  T extends Function              ? T : // can change to never to forbid functions

miyaokamarina

// Licensed under CC BY 4.0.

type $If<X: boolean, Then, Else = empty> = $Call<
    & ((true, Then, Else) => Then)
    & ((false, Then, Else) => Else),
    X,
    Then,
    Else,
>;

miyaokamarina

const regexp = (xs, ...ys) => (xs2, ...ys2) =>
    new RegExp(
        String.raw(xs, ...ys).replace(
            // Find additional escape sequences,
            // spaces, line breaks, comments:
            /\\[#\n ]|#.*$|[\n ]/gm,
            // Remove spaces, line breaks, comments,
            // unescape additional sequences:
            x => (x[0] === '\\' ? x[1] : ''),
        ),