How can I capitalize the first letter of each word in a string using JavaScript?

Question

I'm trying to write a function that capitalizes the first letter of every word in a string (converting the string to title case).

For instance, when the input is "I'm a little tea pot", I expect "I'm A Little Tea Pot" to be the output. However, the function returns "i'm a little tea pot".

This is my code:

function titleCase(str) {
  var splitStr = str.toLowerCase().split(" ");

  for (var i = 0; i < splitStr.length; i++) {
    if (splitStr.length[i] < splitStr.length) {
      splitStr[i].charAt(0).toUpperCase();
    }

    str = splitStr.join(" ");
  }

  return str;
}

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

Answer 1

You are not assigning your changes to the array again, so all your efforts are in vain. Try this:

function titleCase(str) {
   var splitStr = str.toLowerCase().split(' ');
   for (var i = 0; i < splitStr.length; i++) {
       // You do not need to check if i is larger than splitStr length, as your for does that for you
       // Assign it back to the array
       splitStr[i] = splitStr[i].charAt(0).toUpperCase() + splitStr[i].substring(1);     
   }
   // Directly return the joined string
   return splitStr.join(' '); 
}

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