Title Case a Sentence1

Hi, I do not understand why my code is not working. When I try to run it, I get this message:

TypeError: str.join is not a
function. (In str.join(‘ ‘),
‘str.join’ is not defined.)

Thanks in advance :smiley:

Your code so far

function titleCase(str) {
  str = str.toLowerCase().split(' ');
  for (var i = 0; i < str.length; i++) {
    str = str[i].charAt(0).toUpperCase() + str[i].slice(1);
  return str.join(' ');

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

Your browser information:

Your Browser User Agent is: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/604.3.5 (KHTML, like Gecko) Version/11.0.1 Safari/604.3.5.

Link to the challenge:

In your for loop you set str to a string, but .join() is an array method.