使用JavaScript的设计模式实现的一些示例是什么？

const Singleton = (function () {
  let instance;

  function createInstance() {
    return {
      publicMethod: function () {
        console.log('This is a public method');
      },
    };
  }

  return {
    getInstance: function () {
      if (!instance) {
        instance = createInstance();
      }
      return instance;
    },
  };
})();

const instance1 = Singleton.getInstance();
const instance2 = Singleton.getInstance();

console.log(instance1 === instance2); // 输出 true，因为两个实例是相同的对象

function createPerson(name, age) {
  return {
    name: name,
    age: age,
    sayHello: function () {
      console.log(`Hello, my name is ${this.name} and I am ${this.age} years old.`);
    },
  };
}

const person1 = createPerson('Alice', 30);
const person2 = createPerson('Bob', 25);

person1.sayHello(); // 输出 "Hello, my name is Alice and I am 30 years old."
person2.sayHello(); // 输出 "Hello, my name is Bob and I am 25 years old."

const eventEmitter = new EventEmitter();

eventEmitter.on('message', function (message) {
  console.log(`Received message: ${message}`);
});

eventEmitter.emit('message', 'Hello, world!'); // 输出 "Received message: Hello, world!"

const eventEmitter = new EventEmitter();

eventEmitter.on('user-login', function (user) {
  console.log(`User ${user.name} has logged in.`);
});

eventEmitter.on('user-logout', function (user) {
  console.log(`User ${user.name} has logged out.`);
});

eventEmitter.emit('user-login', { name: 'Alice' }); // 输出 "User Alice has logged in."
eventEmitter.emit('user-logout', { name: 'Alice' }); // 输出 "User Alice has logged out."