JavaScript Formatter Online

How JavaScript formatting works

The formatter tokenises your code — splitting it into strings, template literals, regular expressions, comments, identifiers and operators — and then re-prints it with consistent indentation. Each opening brace starts a new indented block, each closing brace ends one, and each statement that ends in a semicolon moves to its own line. Constructs that keep their own punctuation, like a for (;;) header, are recognised so their inner semicolons do not trigger a line break.

Because the tool understands strings, templates and regex, characters that look structural but live inside a literal — a brace in a template string, a slash in a regex — are never misread. Your spacing inside expressions is preserved, so familiar code like a = b + c stays the way you wrote it while the overall shape is cleaned up.

How to format JavaScript

• Copy the JS from a file, a bundle, a console snippet or a minified library.
• Paste it into the input panel.
• Pick an indent width — 2 spaces is the JavaScript community default, 4 spaces and tabs are also supported.
• Copy the formatted result or download it as a .js file.

Detection handles the common case automatically. For a tiny ambiguous fragment, switch the language selector to JavaScript to force the right mode.

Comments and modern syntax

Both line comments (//) and block comments (/* … */) are preserved and placed sensibly, so the explanations in your code are not lost. Modern syntax is handled too: arrow functions, template literals, optional chaining (?.), nullish coalescing (??), spread (...) and the full set of assignment and comparison operators are all tokenised correctly.

The result is deterministic — the same input always produces the same output — which makes the formatter useful as a quick way to normalise a snippet before pasting it into a code review or a bug report.

Reading minified code

One of the most common reasons to format JavaScript is to read a minified file. When a production bundle throws an error on line 1, column 18,000, beautifying it turns that single line into hundreds of readable ones so you can find the function that actually failed. The same applies to snippets copied from a CDN, an obfuscated widget or an inline handler buried in a page.

Formatting does not rename variables or undo minification semantically — short names stay short — but it restores the whitespace and line structure that make the control flow visible, which is usually all you need to understand what the code is doing.

Private by design

Your JavaScript may contain API endpoints, business logic or unreleased features. This formatter never sends it anywhere — all tokenising and printing happen locally in your browser. Confirm it by watching the network tab while you format, or by disconnecting from the internet and watching the tool keep working. Local processing also means there is no upload delay, so even a large file reflows instantly.