Info

http://stackoverflow.com/questions/12539574/whats-the-best-way-most-efficient-to-turn-all-the-keys-of-an-object-to-lower

Preparation code

 
<script>
  Benchmark.prototype.setup = function() {
    
    var obj = {
        "SomeThing" : 2,
        "OthErThing" : 9,
        "AnotherThing" : 10000,
        "OhAndOneMoreThing" : 193013923,
        "aQuiteLargeStringaQuiteLargeStringaQuiteLargeString" : 29320381,
        "SomeThing2" : 2,
        "OthErThing2" : 9,
        "AnotherThing2" : 10000,
        "OhAndOneMoreThing2" : 193013923,
        "aQuiteLargeStringaQuiteLargeStringaQuiteLargeString2" : 29320381,
        "SomeThing3" : 2,
        "OthErThing3" : 9,
        "AnotherThing3" : 10000,
        "OhAndOneMoreThing3" : 193013923,
        "aQuiteLargeStringaQuiteLargeStringaQuiteLargeString3" : 29320381,
        "SomeThing4" : 2,
        "OthErThing4" : 9,
        "AnotherThing4" : 10000,
        "OhAndOneMoreThing4" : 193013923,
        "aQuiteLargeStringaQuiteLargeStringaQuiteLargeString4" : 29320381,
        "SomeThing5" : 2,
        "OthErThing5" : 9,
        "AnotherThing5" : 10000,
        "OhAndOneMoreThing5" : 193013923,
        "aQuiteLargeStringaQuiteLargeStringaQuiteLargeString5" : 29320381
    }
  };
</script>

Test runner

Warning! For accurate results, please disable Firebug before running the tests. (Why?)

Java applet disabled.

  var keys = Object.keys(obj);
  var n = keys.length;
  while (n--) {
    var key = keys[n];
    if (key !== key.toLowerCase()) {
            obj[key.toLowerCase()] = obj[key]
            delete obj[key]
        }
  }

 

// Might be cheaper to just change it, but I doubt it
  var keys = Object.keys(obj);
  var n = keys.length;
  while (n--) {
    var key = keys[n];
    obj[key.toLowerCase()] = obj[key]
    delete obj[key]
  }

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Revisions

You can edit these tests or add even more tests to this page by appending /edit to the URL. Here’s a list of current revisions for this page:

• Revision 1: published by João Jerónimo on 22nd September 2012
• Revision 1: published by João Jerónimo on 22nd September 2012
• Revision 1: published by João Jerónimo on 22nd September 2012
• Revision 2: published on 15th February 2013
• Revision 3: published on 27th February 2013

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