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About JS Formatter Online
This tool reformats JavaScript source code for consistent style and readability. It re-indents nested blocks, normalises spacing around operators, breaks long lines at sensible points, and standardises quote style and semicolon placement.
Useful when reading minified bundles you've extracted from a website, when normalising code from collaborators with different editor settings, or when preparing JavaScript for code review.
The formatter handles modern JavaScript syntax: ES2024+ features, JSX, TypeScript types, async/await, optional chaining, and template literals. It uses sensible defaults inspired by Prettier but with controls for those who prefer different conventions.
How to use this tool
How to pretty-print minified or jumbled JavaScript
Paste the JavaScript
Drop the minified or messy source into the "JS" field. The tool understands ES modules, JSX-free TypeScript, async/await, optional chaining — modern syntax in general. Files with `<script>` wrappers won't work; paste just the code.
Press Run
Result returns a single `formatted` field with consistent semicolons, two-space indentation, and one statement per line. String quotes are normalised to whichever style your input mostly used; comments are preserved verbatim.
What it doesn't do
No linting, no rule enforcement (no-unused-vars, etc.), no AST-level refactor. To enforce a style across a codebase use prettier or eslint --fix in your build. This tool's a one-shot pretty-printer, not a stylesheet enforcer.
Round-trip safety
Formatted JS executes identically to the input — semantics are preserved. Re-minify before deploy with terser or esbuild; the formatted form is for humans, not for the wire.