import { Equal, Expect } from "../helpers/type-utils";
type Maybe<T> = T | null | undefined;
type tests = [
Expect<Equal<Maybe<string>, string | null | undefined>>,
Expect<Equal<Maybe<number>, number | null | undefined>>,
Expect<Equal<Maybe<boolean>, boolean | null | undefined>>,
Expect<Equal<Maybe<null>, null | undefined>>
];标签：Typescript,undefined,Maybe,Expect,Easy,null,type From： https://www.cnblogs.com/Answer1215/p/16974657.html