FreeCodeCamp Title Case A Sentence Sample Solution

function titleCase(str) {
  var arr = str.toLowerCase().split(' ');
  var arr2 = [];
  for(var i=0; i<arr.length; i++){
    arr2.push(arr[i].substring(0,1).toUpperCase()+arr[i].substring(1,arr[i].length));
  }
  return arr2.join(' ');
}

titleCase("I'm a little tea pot");