Typescripe類型體操 - FlipArguments

題目

中文

實現 lodash 中_.flip方法的類型版本

FlipArguments<T>類型接收泛型參數 T 並返回一個函數類型, 且此函數類型有和 T 相同的返回類型但其參數的順序是倒過來的

English

Implement the type version of lodash's _.flip.

Type FlipArguments<T> requires function type T and returns a new function type which has the same return type of T but reversed parameters.

For example:

type Flipped = FlipArguments<
    (arg0: string, arg1: number, arg2: boolean) => void
>;
// (arg0: boolean, arg1: number, arg2: string) => void

答案

type FlipArray<T extends any[]> = T extends [...infer L, infer R]
    ? [R, ...FlipArray<L>]
    : T;
type FlipArguments<T extends Function> = T extends (
    ...a: infer R
) => infer TReturn
    ? (...a: FlipArray<R>) => TReturn
    : never;

在線演示