Typescript 如何准确推断当前数据类型

Question

如何修改getDataBykey方法，使其能够根据field的值推断出准确的返回类型，而非联合类型

---

type Data = {
    name: string,
    age: number,
    isMan: boolean,
};

function getDataByKey(data: Data, field: keyof Data) {
    return data[field];
}


const result = getDataByKey({ name: "lee", age: 22, isMan: true }, "name");

Answer 1

type Data = {
    name: string,
    age: number,
    isMan: boolean,
};

function getDataByKey<K extends keyof Data>(data: Data, field: K): Data[K] {
    return data[field];
}