在javascript对象中查找键并返回结果

const person = {
  name: 'John',
  age: 30,
};

const name = person.name;
console.log(name); // 输出：'John'

const person = {
  name: 'John',
  age: 30,
};

const property = 'name';
const name = person[property];
console.log(name); // 输出：'John'

const person = {
  name: {
    first: 'John',
    last: 'Doe',
  },
  age: 30,
};

const firstName = person.name.first;
console.log(firstName); // 输出：'John'

const person = {
  name: 'John',
  age: 30,
};

const hasName = person.hasOwnProperty('name');
console.log(hasName); // 输出：true

const hasAddress = person.hasOwnProperty('address');
console.log(hasAddress); // 输出：false