在Typescript中访问动态/函数类的属性

interface MyClass {
    name: string;
}

function foo(obj: any) {
    // 断言obj为MyClass类型
    const myObj = obj as MyClass;
    console.log(myObj.name);
}

const obj = { name: "John" };
foo(obj);

interface MyClass {
    name?: string;
}

function foo(obj: MyClass) {
    console.log(obj?.name);
}

const obj = { name: "John" };
foo(obj);

interface MyObject {
    [key: string]: string;
}

const obj: MyObject = {
    name: "John",
    age: "30"
};

console.log(obj["name"]);  // 输出 "John"
console.log(obj["age"]);   // 输出 "30"