Convert a String to Title Case in JavaScript (Exercise)

The challenge

Write titleCase(sentence) that makes the first letter of each word uppercase and the rest lowercase.

Example

titleCase("the lion KING")  // "The Lion King"

Try it

Write your answer below, then press Check my answer. Your code runs right here in your browser, and the tests tell you what works.

Your solution

It prints

What the tests check

titleCase("the lion KING") gives "The Lion King"
titleCase("welcome") gives "Welcome"
titleCase("a b c") gives "A B C"

Hints

Stuck? Open one hint at a time. Try again after each one.

Hint 1

split(" ") into words, fix each word, then join(" ").

Hint 2

For one word: word[0].toUpperCase() + word.slice(1).toLowerCase().

A solution

There’s always more than one right way. Read it, make sure you understand it, then try writing it yourself without looking.

Show one possible solution

Solution

function titleCase(sentence) {
  const words = sentence.split(" ");
  const fixed = [];
  for (const w of words) {
    fixed.push(w[0].toUpperCase() + w.slice(1).toLowerCase());
  }
  return fixed.join(" ");
}

Learn what you need

This exercise uses what Grade 7: Arrays: Lists of Things teaches. Read those notes first if any of it is new.

Convert a string to title case