技术

TypeScript 挑战（六）- 实现内置的Exclude <T，U>

学习记录 - 实现内置的Exclude <T，U>

题目简介

实现内置的Exclude <T，U>

从T中排除可分配给U的那些类型

测试用例

import { Equal, Expect, ExpectFalse, NotEqual } from '@type-challenges/utils'

type cases = [
    Expect<Equal<MyExclude<"a" | "b" | "c", "a">, Exclude<"a" | "b" | "c", "a">>>,
    Expect<Equal<MyExclude<"a" | "b" | "c", "a" | "b">, Exclude<"a" | "b" | "c", "a" | "b">>>,
    Expect<Equal<MyExclude<string | number | (() => void), Function>, Exclude<string | number | (() => void), Function>>>,
]

答案

type MyExclude<T, U> = T extends U ? never : T;