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JavaScript Formatter

Format and beautify JavaScript, ES6+, and Node.js code with Prettier-style indentation. Handles arrow functions, async/await, classes, destructuring, and template literals.

📥 Input

📤 Output

Ready — paste code and click Format · Ctrl+Enter to format

Lines: — Size: —

Load example: ▶ Async ▶ Class

📊 Stats

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Lines

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Size

💡 Quick Reference

2 spacesPrettier default

===Always strict equal

const/letNo var

=>Arrow functions

async/awaitOver .then()

🔗 Related Tools

JavaScript Formatting with Prettier

Prettier is the dominant JavaScript code formatter, used by the vast majority of JavaScript projects. It uses 2-space indentation by default, enforces consistent quote styles, adds trailing commas, and formats arrow functions, template literals, and object destructuring according to a single opinionated style. Running Prettier on save (via editor plugins or pre-commit hooks) eliminates all formatting-related code review comments.

Frequently Asked Questions

Always use === (strict equality). The == operator performs type coercion, leading to surprising results like 0 == false being true or '' == false being true. Strict equality === checks both value and type without coercion, behaving predictably. ESLint's eqeqeq rule enforces this.

var is function-scoped and hoisted — it can be accessed before declaration (as undefined). let is block-scoped and not hoisted — it exists only within its enclosing block. const is block-scoped and must be initialised at declaration; the binding cannot be reassigned (though object properties can still change). Modern JavaScript: always use const by default, let when you need to reassign, never var.

JavaScript is single-threaded — it runs one piece of code at a time. The event loop is the mechanism that allows JavaScript to handle asynchronous operations (timers, network requests, user events) without blocking. When an async operation completes, its callback is added to a queue. The event loop continuously checks if the call stack is empty and, if so, moves the next queued callback onto the stack to execute.

Done!

What is JavaScript Formatter?

JavaScript Formatter is a free online utility designed to help developers, designers, and technical professionals work more efficiently. This tool runs entirely in your browser — no installation required, no data sent to any server.

How to Use JavaScript Formatter

Paste or type your input in the editor area above.
Click the action button to process your content.
Copy the output or download the result.

Key Features

100% Free — No registration or payment required.
Client-side Processing — Your data never leaves your browser.
Instant Results — Get output in milliseconds.
No Installation — Works directly in your web browser.
Mobile Friendly — Works on phones, tablets, and desktops.

Who Uses JavaScript Formatter?

This tool is widely used by web developers, software engineers, data analysts, students, and IT professionals who need a quick and reliable way to process data without setting up complex software environments.

Frequently Asked Questions

Is JavaScript Formatter free to use?

Yes, JavaScript Formatter is completely free. There are no hidden charges, no subscription fees, and no account required.

Is my data safe when using JavaScript Formatter?

Absolutely. All processing happens locally in your browser. No data is uploaded to any server, making it completely private and secure.

Can I use JavaScript Formatter on mobile devices?

Yes, JavaScript Formatter is fully responsive and works on all modern browsers and devices including smartphones and tablets.

Do I need to install anything to use JavaScript Formatter?

No installation is required. Simply open the page in your browser and start using it immediately.

How accurate is JavaScript Formatter?

JavaScript Formatter uses industry-standard algorithms to ensure accurate and reliable results every time.