Typescript Tuple Operators

tuple-operators.ts

type SliceTuple<
  T extends any[],
  TMaxItem extends number = 2,
  R extends any[] = [],
  P extends any[] = [],
  I extends any[] = []
> = {
  0: SliceTuple<T, TMaxItem, R, Prepend<T[Pos<I>], P>, Next<I>>;
  1: Reverse<Prepend<Reverse<P>, R>>;
  2: SliceTuple<T, TMaxItem, Prepend<Reverse<P>, R>, [T[Pos<I>]], Next<I>>;
  // if empty value
  3: [];
}[T[0] extends undefined
  ? 3
  : Pos<I> extends Length<T>
  ? 1
  : Length<P> extends TMaxItem
  ? 2
  : 0];

type MergeTuple<
  T extends any[],
  R extends { [key: string]: any } = {},
  I extends any[] = []
> = {
  0: MergeTuple<T, { [key in T[Pos<I>][0]]: T[Pos<I>][1] } & R, Next<I>>;
  1: R;
}[Pos<I> extends [] ? 1 : Pos<I> extends Length<T> ? 1 : 0];

type PipeTuple<T extends any[], R extends any[] = [], I extends any[] = []> = {
  0: PipeTuple<T, T[Pos<I>] | R, Next<I>>;
  1: R;
}[T[0] extends undefined
  ? 1
  : Pos<I> extends []
  ? 1
  : Pos<I> extends Length<T>
  ? 1
  : 0];