JavaScript Formatter

The JavaScript Formatter takes minified, cramped, or inconsistently indented JavaScript and rewrites it with clean line breaks and predictable indentation so it becomes readable again. You paste the code, choose your indent size, and the tool walks through the source, adding a new line and adjusting the indent level around braces, brackets, and parentheses, and after semicolons. It is the quick way to make a wall of compressed code legible enough to understand or debug.

This is an indent-based pretty printer rather than a full parser, and it is deliberately honest about that. It tracks whether it is inside a string so that braces and semicolons within quotes are left untouched, which handles the most common cause of naive formatters mangling code. It does not build a complete syntax tree, so it will not rewrite expressions or enforce a style guide, but for making minified or messy code readable it is fast and dependable.

Everything runs locally in your browser, so the code you paste, which might be proprietary or unreleased, is never uploaded or stored. There are no accounts, no size caps beyond your browser's memory, and no waiting on a server. You get the reformatted result instantly and can copy it straight back into your editor or download it as a file.

Features

• Adds line breaks and indentation around braces, brackets and parentheses and after semicolons.
• Tracks string context so characters inside quotes and template literals are never reformatted.
• Lets you choose the indent size so the output matches your project's style.
• Turns single-line minified code into a readable multi-line layout in one step.
• Handles escaped quotes correctly so strings with special characters stay intact.
• Reports the number of output lines so you can see how much the code expanded.
• Runs entirely in your browser with no upload, keeping proprietary code private.

How to use JavaScript Formatter

1. Paste your minified or messy JavaScript into the input box.
2. Choose the indent size you prefer, such as two or four spaces.
3. Read the reformatted code in the output panel with consistent indentation and line breaks.
4. Copy the result back into your editor, or download it as a file for later.
5. If you need strict, style-guide formatting, run the output through a full formatter in your toolchain.

Benefits

• Developers make minified library code readable enough to understand what it is doing.
• Learners study compressed examples by expanding them into a clear, indented layout.
• Reviewers quickly scan an unfamiliar snippet after giving it consistent structure.
• Support engineers inspect production bundles to trace a bug back to its source logic.
• Anyone pasting code from a one-line source gets a legible version without installing tools.
• Because formatting is local, proprietary or unreleased code never leaves the browser.

Minification strips out the whitespace and line breaks that make code readable in order to shrink file size for delivery. That is great for performance but terrible for comprehension, and this formatter reverses the visual part of that process by reintroducing structure. It increases the indent level when it opens a block or grouping and decreases it when the block closes, giving you the familiar staircase layout that reveals how the code is nested.

The key to formatting code safely is respecting strings, because a brace or semicolon inside a quoted string is data, not structure. This tool tracks when it is inside single quotes, double quotes, or template literals and leaves that content alone, also honouring the backslash escape so an escaped quote does not prematurely end a string. That single behaviour prevents the most common way naive formatters corrupt code.

It is important to be clear that this is not a complete JavaScript parser and does not build an abstract syntax tree. It will not reflow long expressions, align complex arguments, or apply a specific style guide, and extremely unusual code such as regular-expression literals with braces may not format perfectly. For readability of minified or messy code it works well, but for canonical, rule-driven formatting use a full formatter in your build toolchain.