/**
 * HOP ref.
 */

var has = Object.prototype.hasOwnProperty;

/**
 * Return own keys in `obj`.
 *
 * @param {Object} obj
 * @return {Array}
 * @api public
 */

exports.keys = Object.keys || function(obj){
  var keys = [];
  for (var key in obj) {
    if (has.call(obj, key)) {
      keys.push(key);
    }
  }
  return keys;
};

/**
 * Return own values in `obj`.
 *
 * @param {Object} obj
 * @return {Array}
 * @api public
 */

exports.values = function(obj){
  var vals = [];
  for (var key in obj) {
    if (has.call(obj, key)) {
      vals.push(obj[key]);
    }
  }
  return vals;
};

/**
 * Merge `b` into `a`.
 *
 * @param {Object} a
 * @param {Object} b
 * @return {Object} a
 * @api public
 */

exports.merge = function(a, b){
  for (var key in b) {
    if (has.call(b, key)) {
      a[key] = b[key];
    }
  }
  return a;
};

/**
 * Return length of `obj`.
 *
 * @param {Object} obj
 * @return {Number}
 * @api public
 */

exports.length = function(obj){
  return exports.keys(obj).length;
};

/**
 * Check if `obj` is empty.
 *
 * @param {Object} obj
 * @return {Boolean}
 * @api public
 */

exports.isEmpty = function(obj){
  return 0 == exports.length(obj);
};