typescript模板文字中string和keyof类型的用途

interface Person {
  name: string;
  age: number;
}

function greet(person: Person) {
  return `Hello, ${person.name}! You are ${person.age} years old.`;
}

function getPersonProperty<T, K extends keyof T>(obj: T, key: K): T[K] {
  return obj[key];
}

const person: Person = { name: "Alice", age: 30 };
console.log(greet(person)); // 输出: Hello, Alice! You are 30 years old.
console.log(getPersonProperty(person, "name")); // 输出: Alice
console.log(getPersonProperty(person, "age")); // 输出: 30

interface Person {
  name: string;
  age: number;
}

function getPersonInfo<T, K extends keyof T>(person: T, key: K): T[K] {
  return person[key];
}

const person: Person = { name: "Alice", age: 30 };
console.log(getPersonInfo(person, "name")); // 正确
// console.log(getPersonInfo(person, "address")); // 错误，"address" 不是 Person 的键