TypeScript 3.9 | Advanced Types: Adds a type E at the top of a tuple T

Prepend.ts

type Prepend<E, T extends any[]> = ((head: E, ...args: T) => any) extends (
  ...args: infer U
) => any
  ? U
  : T

type Prepend01 = Prepend<string, []> // [string]
type Prepend02 = Prepend<string, [1, 2]> // [string, 1, 2]

// https://medium.com/free-code-camp/typescript-curry-ramda-types-f747e99744ab
// https://github.com/millsp/medium/blob/master/types-curry-ramda/src/index.ts