Format and beautify JavaScript

Minified JavaScript is a single line with every space removed, and code pasted from a chat, a PDF or an old project is often indented in several different styles at once. Either way, reading it is slow. This formatter lays the code out consistently: one statement per line, blocks indented by the width you choose, spaces around operators and after commas, and long chains broken where it helps.

You can pick two spaces, four spaces or tabs, and the brace style your team uses: braces on the same line as the if or function, braces on their own line (Allman style), or the variant that puts else on a new line. Blank lines from the input can be kept (up to two in a row) so the original grouping survives, and long lines can be wrapped at 80 to 120 characters. Modern syntax such as arrow functions, classes, template literals, async/await, optional chaining and spread is handled.

Formatting is done by js-beautify (MIT), about 17 KB compressed and loaded only when you format something here. It is a beautifier, not a compiler: it does not check that your code runs, it cannot rename minified variables back to their original names, and it does not reorder anything. For source that was bundled, a source map from the original build is the only way to recover real names. The code never leaves your browser.