What's the best way (most efficient) to turn all the keys of an object to lower case?

Question

I\'ve come up with

function keysToLowerCase (obj) {
  var keys = Object.keys(obj);
  var n = keys.length;
  while (n--) {
    var key = keys[n]; // \"cache\"         


        

Answer 1

For all values:

to_lower_case = function(obj) {
    for (var k in obj){
        if (typeof obj[k] == "object" && obj[k] !== null)
            to_lower_case(obj[k]);
        else if(typeof obj[k] == "string") {
            obj[k] = obj[k].toLowerCase();
        }
    }
    return obj;
}

Same can be used for keys with minor tweaks.