요구사항 :

객체 예: 

var student = { 

name : "홍길동", 

sex : "남", 

age : 24 };

Sample Output: name,sex,age

코드 :

function _keys(obj) 
 {
    if (!isObject(obj)) return [];
    if (Object.keys) return Object.keys(obj);
    var keys = [];
    for (var key in obj) if (_.has(obj, key)) keys.push(key);
    return keys;
  }
function isObject(obj) 
{
    var type = typeof obj;
    return type === 'function' || type === 'object' && !!obj;
  }
console.log(_keys({red: "#FF0000", green: "#00FF00", white: "#FFFFFF"}));

결과 :

red,green,white