泛型类型中的打字稿值类型

Question

我有使字段成为必需的通用类型

type MakeFieldRequired<T, K extends keyof T> =
    T & Required<Pick<T, K>>

type Data = {
    optional1?: number;
    optional2?: number;
    required: number;
}

const data: Data = {
    required: 1
}

const data2: MakeFieldRequired<Data, 'optional1'> = {
    optional1: 1,
    required: 1
};

我如何制作泛型并直接在那里使用值类型，比如

type MakeOptional2FieldRequired<T>
    = MakeFieldRequired<T, T['optional2']>;

const data3: MakeOptional2FieldRequired<Data> = {
    optional2: 1,
    required: 1
}

Answer 1

为了获得T['optional2']的类型，您需要在T上设置约束。

type MakeOptional2FieldRequired<T extends { optional2: any }> = T['optional2']

但我认为这实际上不是您想要的，因为它将类型作为属性键传递。 相反，只需传递字符串文字

type MakeOptional2FieldRequired<T extends { optional2: any }> = MakeFieldRequired<T, 'optional2'>