Question

I'm already aware that TypeScript does not allow enums as constraints，但是有没有办法-即使是骇人听闻的人-也能获得类似的行为？

export enum StandardSortOrder {
    Default,
    Most,
    Least
}

export enum AlternativeOrder {
    Default,
    High,
    Medium,
    Low
}

export interface IThingThatUsesASortOrder<T extends enum> { // doesn't compile
    sortOrder: T;
}

Answer 1

打字稿中没有这样的约束。最好的办法是使用枚举的基本类型，在这种情况下为number（如果需要使用字符串枚举，则可以使用string或string | number都允许）

export enum StandardSortOrder {
    Default,
    Most,
    Least
}

export enum AlternativeOrder {
    Default,
    High,
    Medium,
    Low
}

export interface IThingThatUsesASortOrder<T extends number> { 
    sortOrder: T;
}

let a: IThingThatUsesASortOrder<StandardSortOrder>
let a2: IThingThatUsesASortOrder<AlternativeOrder>

如何模拟“ T扩展枚举”泛型约束？

1 个答案: