在js中没有循环的情况下找到对象中是否存在此键

function hasKey(obj, key) {
  for (let k in obj) {
    if (k === key) {
      return true;
    }
  }
  return false;
}

const obj = {
  name: 'John',
  age: 25,
  city: 'New York'
};

console.log(hasKey(obj, 'name'));  // 输出 true
console.log(hasKey(obj, 'gender'));  // 输出 false

function hasKey(obj, key) {
  return Object.keys(obj).includes(key);
}

const obj = {
  name: 'John',
  age: 25,
  city: 'New York'
};

console.log(hasKey(obj, 'name'));  // 输出 true
console.log(hasKey(obj, 'gender'));  // 输出 false