如何从联合为共享的对象中获取密钥？答案

【问题标题】：How can I get the keys from an object that is union as shared?如何从联合为共享的对象中获取密钥？
【发布时间】：2022-08-18 01:21:28
【问题描述】：

例如

如果我采用这种类型并将其放入keyof，我永远不会。

type T = {
        items?: string[] | undefined;
        \'items.0.kind\'?: string[] | undefined;
        \'items.0.institution\'?: string[] | undefined;
        \'items.0.started_at\'?: string[] | undefined;
        \'items.0.finished_at\'?: string[] | undefined;
        \'items.0.specialization\'?: string[] | undefined;
        \'items.0.qualification\'?: string[] | undefined;
    } | {
        user_is_blocked?: string[] | undefined;
        jwt_token_is_invalid?: string[] | undefined;
        jwt_token_is_expired?: string[] | undefined;
    }
type Keys = keyof T // === never

标签： typescript

【解决方案1】：

您可以使用条件分配类型对联合的部分进行操作：

type T = {
        items?: string[] | undefined;
        'items.0.kind'?: string[] | undefined;
        'items.0.institution'?: string[] | undefined;
        'items.0.started_at'?: string[] | undefined;
        'items.0.finished_at'?: string[] | undefined;
        'items.0.specialization'?: string[] | undefined;
        'items.0.qualification'?: string[] | undefined;
    } | {
        user_is_blocked?: string[] | undefined;
        jwt_token_is_invalid?: string[] | undefined;
        jwt_token_is_expired?: string[] | undefined;
    }

type Distributive<T> = T extends any ? keyof T: never
type Keys = Distributive<T>

【讨论】：