Change all object keys to camelCase

Object keys in camelCase format

var a = {
  id:1,
  user_name:"Vasily",
  last_name:'Kratij',
  law_types:{
    law_type_id:0,
    name:'All types'
  }
};

function changeKeys(a){
  for(var i in a){  
    var newIndex = _.camelCase(i);
    a[newIndex] = a[i];  
    if (newIndex !== i){
      delete a[i];
    }  
  }
  if (typeof a[newIndex] === 'object'){
    changeKeys(a[newIndex]);
  }
  return a;
}
console.log(a)
console.log(changeKeys(a))