typescript - 创建基于键推断泛型的记录类型

Question

我想做这样的事情：

type PossibleKeys = "foo" | "bar" | "not-bar"; 

type SpecialRecord = Record<PossibleKeys, {
    key: PossibleKeys; // I want to make sure that this key matches the record key. 
    data: number; 
}> ; 



const myRecord = {
    foo: {
        key: "foo", // Should be ok
        data: 9, 
    }, 
    bar : {
        key: "not-bar", // Should error
        data: 10
    }
}; 

也就是说，我想声明我的SpecialRecord类型，以便它强制记录的键与key值的属性匹配。

这可能吗？

标签： typescript

Answer 1

这称为映射对象类型，您可以这样做：

type PossibleKeys = "foo" | "bar" | "not-bar"; 

type SpecialRecord = {
    [K in PossibleKeys ]: {
        key: K; 
        data: number; 
    }
}

const myRecord : SpecialRecord= {
    foo: {
        key: "foo", 
        data: 9, 
    }, 
    bar : {
        key: "not-bar", //Type '"not-bar"' is not assignable to type '"bar"'.(2322)

        data: 10
    }
};