JavaScript Capitalize
Capitalize is not a built-in JavaScript method — it is composed from two: charAt(0).toUpperCase() uppercases the first letter, then slice(1) appends the rest. A perfect first example of chaining functions.
Syntax
str.charAt(0).toUpperCase() + str.slice(1)Examples
| Input | Arguments | Output |
|---|---|---|
| "hello world" | — | "Hello world" |
| "éric" | — | "Éric" |
When to use it
- Format names, titles and labels for display.
Gotchas
- Only capitalises the first character, not every word — chain split(" ") + map to title-case a full sentence.
Try it live
Type your input and see Capitalize transform it instantly.
Want to go further? Chain Capitalize with other functions in the visual Playground — pipe one output into the next and watch your data transform.