使用嵌套类方法创建API (Typescript)

class UserAPI {
    private users: { [key: string]: User } = {};

    // 外部类的方法
    public addUser(username: string, email: string): void {
        const user = new this.User(username, email);
        this.users[username] = user;
    }

    public getUser(username: string): User | undefined {
        return this.users[username];
    }

    // 嵌套类
    public class User {
        private username: string;
        private email: string;

        constructor(username: string, email: string) {
            this.username = username;
            this.email = email;
        }

        public getUsername(): string {
            return this.username;
        }

        public getEmail(): string {
            return this.email;
        }

        public setEmail(email: string): void {
            this.email = email;
        }
    }
}

// 使用示例
const api = new UserAPI();
api.addUser("john_doe", "john@example.com");
const user = api.getUser("john_doe");
if (user) {
    console.log(`Username: ${user.getUsername()}, Email: ${user.getEmail()}`);
}