typescript在这种情况下如何重用类型？

function identity<T>(arg: T): T {
  return arg;
}

// 使用泛型函数
let result = identity<string>("Hello");

class Box<T> {
  private value: T;

  constructor(value: T) {
    this.value = value;
  }

  getValue(): T {
    return this.value;
  }
}

// 使用泛型类
let box = new Box<number>(42);
let value = box.getValue();

interface Repository<T> {
  getById(id: number): T;
  save(entity: T): void;
}

class UserRepository implements Repository<User> {
  getById(id: number): User {
    // 实现具体逻辑
  }

  save(entity: User): void {
    // 实现具体逻辑
  }
}

// 使用泛型接口
let userRepository: Repository<User> = new UserRepository();
let user = userRepository.getById(1);

type Point = { x: number; y: number };
type Color = { color: string };

type ColoredPoint = Point & Color;

let coloredPoint: ColoredPoint = {
  x: 10,
  y: 20,
  color: "red",
};