Is my code sent to any server?

No. All formatting runs in your browser using the Prettier library loaded from a CDN. Your code never leaves your device.

What JavaScript syntax is supported?

Prettier supports ES2020+ including arrow functions, async/await, optional chaining, nullish coalescing, destructuring, template literals, and JSX.

Why does formatting fail on some code?

Prettier is a strict parser — it requires syntactically valid JavaScript. If your code has syntax errors (missing brackets, unmatched quotes, etc.) it will report a parse error. Fix the errors first, then format.

Can I format TypeScript or JSX?

This tool targets standard JavaScript (ES2020). For TypeScript or JSX, the parser may reject type annotations or JSX tags. Use a TypeScript-aware formatter for those files.

What is the print width setting?

Print width (default 80) is the column at which Prettier tries to wrap long lines. It is a soft limit — Prettier will not break strings or identifiers, but will wrap function arguments and object properties to stay within the limit.

JS Formatter

Name: JS Formatter
Availability: InStock
Author: Nham Vu

Paste JavaScript code, choose your indentation style, and get cleanly formatted output instantly — no server, no upload.

Options: Indent: Semicolons Single Quotes Print width:

Input

Output

Click Format to see output

Copied!

Summary

Paste JavaScript code, choose your indentation style, and get cleanly formatted output instantly — no server, no upload.

How it works

Paste or type your JavaScript code into the input panel.
Choose your preferred indentation: 2 spaces, 4 spaces, or tabs.
Toggle the "Semicolons" and "Single Quotes" options to match your style guide.
Click "Format" — the formatted code appears in the output panel instantly.
Copy the result with one click or download it as a .js file.

Use cases

Beautify minified JavaScript files for debugging.
Enforce consistent code style before committing to a repository.
Quickly reformat code pasted from Stack Overflow or documentation.
Inspect third-party scripts to understand their logic.
Format auto-generated JavaScript from build tools or transpilers.
Clean up code snippets before sharing with teammates.

Frequently Asked Questions

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Last updated: 2026-05-29 · Reviewed by Nham Vu