为什么筛选具有未定义键的对象在TypeScript严格模式下出现错误

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

const obj: MyObject = {
  name: "John",
  age: 30,
  address: "123 Main St" // address 键未在 MyObject 接口中定义
};

interface MyObject {
  name: string;
  age: number;
  address?: string; // 使用可选属性
}

const obj: MyObject = {
  name: "John",
  age: 30,
  address: "123 Main St"
};

const obj = {
  name: "John",
  age: 30,
  address: "123 Main St"
} as MyObject & { address?: string };

function hasAddress(obj: MyObject): obj is MyObject & { address?: string } {
  return (obj as any).address !== undefined;
}

if (hasAddress(obj)) {
  console.log(obj.address);
}