js object动态获取

const obj = {
  name: 'Alice',
  age: 30,
  greet: function() {
    console.log(`Hello, my name is ${this.name}`);
  }
};

// 使用点符号
console.log(obj.name); // 输出: Alice

// 使用方括号
console.log(obj['age']); // 输出: 30

// 动态获取属性
const key = 'greet';
obj[key](); // 输出: Hello, my name is Alice

console.log(obj.unknownProperty); // 输出: undefined

if (obj.hasOwnProperty('unknownProperty')) {
  console.log(obj.unknownProperty);
} else {
  console.log('Property does not exist');
}

const obj = {
  'first-name': 'Alice',
  'last-name': 'Smith'
};

console.log(obj['first-name']); // 输出: Alice

const obj = {
  name: 'Alice',
  greet: function() {
    console.log(`Hello, my name is ${this.name}`);
  }
};

const greetFunc = obj.greet;
greetFunc(); // 输出: Hello, my name is undefined

const boundGreet = obj.greet.bind(obj);
boundGreet(); // 输出: Hello, my name is Alice

const dynamicObj = {
  data: {
    users: [
      { id: 1, name: 'Alice' },
      { id: 2, name: 'Bob' }
    ]
  },
  getUserById: function(id) {
    return this.data.users.find(user => user.id === id);
  }
};

const userId = 1;
const user = dynamicObj.getUserById(userId);
console.log(user); // 输出: { id: 1, name: 'Alice' }