function (v) {
  var result = 0
  var key
  for (key in v) {
      v.hasOwnProperty(key) && result++
  }
  return result
}
function (v) {
  var result = 0
  var key
  for (key in v) {
      v.hasOwnProperty(key) && result++
  }
  return result
}
function ( v ) { var result = 0 var key for ( key in v ) { v . hasOwnProperty ( key ) && result ++ } return result }
return number
- counting key of object
return number - counting key of object