在JavaScript中获取具有键值的对象数据

const obj = {
  name: 'Alice',
  age: 25
};

const name = obj.name; // 获取 'Alice'

const obj = {
  name: 'Alice',
  age: 25
};

const key = 'name';
const name = obj[key]; // 获取 'Alice'

const obj = {
  name: 'Alice',
  age: 25
};

const keys = Object.keys(obj); // 获取 ['name', 'age']
const values = Object.values(obj); // 获取 ['Alice', 25]

const obj = {
  name: 'Alice',
  age: 25
};

const entries = Object.entries(obj); // 获取 [['name', 'Alice'], ['age', 25]]

const obj = {
  name: 'Alice',
  age: 25
};

for (const key in obj) {
  if (obj.hasOwnProperty(key)) {
    console.log(`${key}: ${obj[key]}`);
  }
}
// 输出:
// name: Alice
// age: 25

const obj = {
  name: 'Alice'
};

const age = obj.age; // age 是 undefined

const age = obj.age || 'Unknown'; // 如果 age 不存在，返回 'Unknown'

const key = 'name';
const obj = {
  name: 'Alice'
};

const value = obj[key]; // 获取 'Alice'

for (const [key, value] of Object.entries(obj)) {
  console.log(`${key}: ${value}`);
}