JavaScript Formatter
FormattersFormat and beautify JavaScript with Prettier. Supports ES2022+, CommonJS, ESM, async/await, optional chaining, and template literals. 100% browser-based.
About JavaScript Formatter
The JavaScript Formatter is a Prettier-powered, browser-based tool that instantly beautifies raw, minified, or inconsistently indented JavaScript into clean, standardised output. Using Prettier's Babel parser with the estree plugin, it handles the full modern JavaScript language surface — ES2022+, CommonJS and ESM modules, async/await, optional chaining (`?.`), nullish coalescing (`??`), class fields, and template literals — with configurable indentation. All formatting runs in a Web Worker so even large files process without blocking the page. Your code never leaves the browser.
Features
- ✓Powered by Prettier's Babel parser — the most widely used JavaScript formatter
- ✓Full ES2022+ support: optional chaining, nullish coalescing, class fields, top-level await
- ✓Handles CommonJS (require/module.exports) and ESM (import/export) module syntax
- ✓Supports async/await, generators, destructuring, and spread operators
- ✓Configurable indentation: 2 spaces, 4 spaces, or tab; print width 80
- ✓Semicolons enabled, double quotes — Prettier's recommended defaults
- ✓Web Worker execution — formatting never blocks the UI
- ✓Syntax-highlighted CodeMirror editor for both input and output
- ✓One-click clipboard copy of formatted output
- ✓Real-time byte-savings stats (input vs output size)
- ✓Language picker — instantly switch to TypeScript, JSX, TSX, or 20+ other formatters
- ✓Mobile-responsive layout with a dedicated Format button
- ✓100% client-side — your code never leaves the browser
Common Use Cases
- Beautifying minified third-party JavaScript before debugging in production
- Normalising code style before committing to a shared repository
- Formatting JavaScript snippets before pasting into code reviews or Stack Overflow
- Cleaning up auto-generated code from build tools or scaffolding scripts
- Preparing readable JS examples for documentation, blog posts, or tutorials
- Standardising indentation and quote style across a team's JavaScript codebase
Frequently Asked Questions
QWhich version of JavaScript does this support?
ES2022 and below, including all stage-4 proposals adopted in ES2022 such as class static blocks, at(), and Object.hasOwn(). Experimental stage-3 proposals may not be supported.
QWhat are the default formatting settings?
Prettier defaults: print width 80, double quotes, semicolons enabled, 2-space indentation. You can change the indent size with the indentation picker.
QIs my code sent to a server?
No. All formatting runs locally in a Web Worker inside your browser. Nothing is transmitted to any server.
QWhat is the difference between the JavaScript and TypeScript formatters?
The JavaScript formatter uses Prettier's Babel parser, which handles plain JS. The TypeScript formatter uses Prettier's TypeScript parser, which preserves type annotations, generics, decorators, and TypeScript-specific syntax.