JavaScript Formatter

A fast, client-side JavaScript formatter that tidies code according to configurable style rules, designed for developers seeking consistent formatting.

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2,348+
Total Calculations Run
< 15ms
Browser Execution Speed
100%
Client-Side Privacy
4.9 / 5.0
User Satisfaction

Worked Example & Common Values

Below is a sample worked calculation demonstrating how JavaScript Formatter processes input data instantly inside your browser.

Sample Input Minified string: {"id":1,"status":"active","roles":["admin"]}
Computed Result { "id": 1, "status": "active", "roles": [ "admin" ] }
Execution Mode Client-Side In-Browser JS
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About This Tool

This tool formats JavaScript source code to a consistent style using a configurable rule set. It targets individual developers, teams enforcing shared code style guides, educators creating teaching materials, and code reviewers seeking readable diffs. Given raw JavaScript, it outputs a standardized, well-formatted version that improves readability, reduces cognitive load during reviews, and helps maintain uniform code across projects with minimal manual edits.
Conceptually, formatting proceeds by parsing the input into a safe internal representation (AST or token stream) and re-emitting code according to the selected rules. Supported options include indentation (spaces or tabs and size), semicolon usage, quotes (single or double), trailing comma policy, and a maximum line length. The tool aims to be deterministic: the same input and settings produce the same output. It preserves comments and template literals where safe to avoid altering intent.
Unique value lies in in-browser operation, speed, and explicit control over style without performing linting or semantic analysis. Typical use cases include preparing code for pull requests, teaching style guidelines, refactoring sessions, and onboarding new contributors. It differentiates itself from generic beautifiers by combining a clear rule set with predictable results and easy export of formatted code for CI pipelines or editors.

How to Use

  1. Provide the JavaScript source code to format.
  2. Choose formatting options: indentation style, indent size, semicolon usage, and quote style.
  3. Run the formatter to generate the reformatted code.
  4. Review the formatted output and applied rules metadata.
  5. Copy or export the formatted code for integration into your project.
How to use js formatter online

Frequently Asked Questions

Find Quick Answers

What languages are supported?
Primarily JavaScript is supported. The formatter handles modern ES syntax (ES2020+); TypeScript-style typings or non-JS constructs are not fully parsed and preserved, with emphasis on JavaScript formatting.
What options can be configured?
Indentation style (spaces or tabs) and size, semicolon usage, quotes, trailing commas, and maximum line length. Some style presets can be chosen, and advanced users may adjust brace style and wrapping behavior.
What happens if the code can't be formatted?
If parsing fails or the input uses unsupported syntax, the formatter returns the original code and provides metadata about the issue; no unintended semantic changes occur.
Is data sent to a server?
No network requests are made when used in-browser; code remains on the client unless the user exports or copies it for transfer.

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