Includes 实现

在类型系统里实现JavaScript的Array.includes方法，这个类型接受两个参数，返回的类型要么是true要么是false。

例如：


type isPillarMen = Includes<['Kars', 'Esidisi', 'Wamuu', 'Santana'], 'Dio'> // expected to be `false`

查看解答

type MyEqual<A, B> = (<T>() => T extends A ? 1:0) extends (<T>() => T extends B ? 1 :0) ? true : false

type Includes<T extends readonly any[], U> = T extends [infer A, ...infer B] ?
  MyEqual<A, U> extends true ?
    true :
    (B extends [] ?
      false :
      (Includes<B, U> extends true ?true : false)
    )
  : false

Includes 实现 #

Includes 实现