JavaScript Formatter
LiveBeautify and format JavaScript and TypeScript code with proper indentation.
Understanding JavaScript
JavaScript powers dynamic behavior across billions of web pages, server-side applications (Node.js, Deno, Bun), mobile apps (React Native, Ionic), and desktop software (Electron). With multiple coding styles in the ecosystem — semicolons vs no semicolons, tabs vs spaces, trailing commas vs none — maintaining consistent formatting across teams and projects requires automated tooling. Minified production JavaScript, transpiled output from TypeScript or Babel, and auto-generated code from scaffolding tools all require formatting to become readable.
Format messy, minified, or poorly indented JavaScript and TypeScript code into clean, readable, properly structured code. Handles functions, objects, arrays, arrow functions, and modern ES6+ syntax.
The Devkitr JavaScript Formatter expands minified or poorly formatted JavaScript into clean, readable code with configurable indentation, semicolons, quote style, and line width. It handles modern ES2024 syntax including optional chaining, nullish coalescing, private class fields, top-level await, decorators, and JSX expressions.
In a typical development workflow, JavaScript Formatter becomes valuable whenever you need to beautify and format javascript and typescript code with proper indentation. Whether you are working on a personal side project, maintaining production applications for a company, or collaborating with a distributed team across time zones, having a reliable browser-based formatting tool eliminates the need to install desktop software, write one-off scripts, or send data to third-party services that may log or retain your information. Since JavaScript Formatter processes everything locally on your device, your data stays private and your workflow stays uninterrupted — open a browser tab, paste your input, get your result.
Key Features
Modern ECMAScript Support
Handles ES2024 features including optional chaining (?.), nullish coalescing (??), private fields (#), top-level await, and pattern matching syntax.
Configurable Code Style
Set indentation (2/4 spaces or tabs), semicolons (always/never), quote style (single/double), and trailing commas to match your project's Prettier or ESLint config.
JSX Formatting
Formats JSX expressions in React components with proper indentation, multi-line prop alignment, and self-closing tag handling.
Minified Code Expansion
Expands single-line minified production bundles back into readable multi-line code with restored control flow and function boundaries.
How to Use JavaScript Formatter
Paste JavaScript Code
Copy minified, transpiled, or unformatted JavaScript from production bundles, build output, console snippets, or any source.
Configure Style Rules
Set your preferred indentation, semicolons, quotes, trailing commas, and line width to match your project standards.
Review Formatted Output
The formatted code appears with proper indentation, whitespace, line breaks between functions, and consistent style throughout.
Copy to Your Editor
Paste the clean code into your IDE, commit it to version control, or use it for code review and documentation.
Use Cases
Debugging Minified Production Code
Expand minified JavaScript to set breakpoints, trace execution flow, and understand error stack traces referencing compressed files.
Standardizing Team Code Style
Format JavaScript from different contributors to a consistent style before review, eliminating formatting-only changes from pull requests.
Reading Transpiled Output
Format TypeScript or Babel transpiler output to understand what generated code your runtime actually executes.
Cleaning Copied Code Snippets
Format code snippets from Stack Overflow, tutorials, or documentation before integrating them into your codebase.
Pro Tips
Match your formatter settings to your project's .prettierrc or .eslintrc configuration to ensure consistency with automated formatting.
Format JavaScript before diffing two versions — consistent formatting makes actual logic changes visible instead of style noise.
Use the formatted output to check that minification preserved the code's logic — compare formatted original against formatted minified.
When formatting large files (5000+ lines), the browser tab may briefly freeze — this is normal for client-side parsing of large JavaScript ASTs.
Common Pitfalls
Formatting JavaScript that contains template literal expressions as plain strings
Fix: Template literals with ${} expressions must be parsed as JavaScript, not as string content. Ensure the formatter handles ES6+ template syntax.
Assuming formatted code behaves differently than minified code
Fix: Formatting changes only whitespace and line breaks (ASI notwithstanding). The formatted and minified versions execute identically in JavaScript engines.
Manually formatting instead of using automated tools in your workflow
Fix: Configure Prettier or ESLint autofix in your editor and CI pipeline. Manual formatting is slow, inconsistent, and should be reserved for ad-hoc needs.
Frequently Asked Questions
QDoes it support TypeScript?
Yes. The formatter handles both JavaScript and TypeScript code, including type annotations and interfaces.
QDoes it support ES6+ syntax?
Yes. Arrow functions, template literals, destructuring, async/await, optional chaining, and other modern syntax are fully supported.
QCan it unminify bundled JavaScript?
Yes. It can beautify minified production code to make it readable for debugging, though variable names remain minified.
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