Capitalize Words

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BeginnerStrings

Task

Implement `capitalizeWords(sentence)` that upper-cases the **first letter of every word** and lower-cases the rest: `'javaScript IS fun'` → `'Javascript Is Fun'`. Treat runs of whitespace as a single separator.

Hints

0 / 3

sentence.split(/\s+/) splits on one-or-more spaces.
word[0].toUpperCase() + word.slice(1).toLowerCase() transforms one word.
Remember to join(' ') back together.

Verification tests

capitalizeWords("hello world")→ "Hello World"
capitalizeWords("javaScript IS fun")→ "Javascript Is Fun"
capitalizeWords("single")→ "Single"
capitalizeWords(" spaced out ")→ "Spaced Out"

⚠️ Reveal official solutions

Try solving it yourself first — struggling is where the learning happens.

Recommended — the map/join pipeline reads best.

function capitalizeWords(sentence) {
  return sentence
    .trim()
    .split(/\s+/)
    .map((w) => w[0].toUpperCase() + w.slice(1).toLowerCase())
    .join(' ');
}

Same logic step by step; use when asked to avoid higher-order functions.

function capitalizeWords(sentence) {
  const words = sentence.trim().split(/\s+/);
  const out = [];
  for (const w of words) {
    if (w.length === 0) continue;
    out.push(w[0].toUpperCase() + w.slice(1).toLowerCase());
  }
  return out.join(' ');
}

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