Documentation Index
Fetch the complete documentation index at: https://mintlify.com/beautifier/js-beautify/llms.txt
Use this file to discover all available pages before exploring further.
Synopsis
js-beautify [options] <file ...>
npm install -g js-beautify), the js-beautify executable is available on your PATH. Beautified output is written to stdout by default.
Pass - as a filename to read from stdin. When no files are provided and no stdin pipe is detected, the CLI prints an error and usage information.
Options
I/O options
| Flag | Long form | Description |
|---|
-f | --file | Input file(s). Pass - for stdin. |
-r | --replace | Write output in-place, overwriting the input file. |
-o | --outfile | Write output to a specific file instead of stdout. |
| --config | Path to a JSON config file. |
| --type | Select beautifier type: js, css, or html. Does not filter input files — only selects which beautifier to run. Default: js. |
-q | --quiet | Suppress logging to stdout. |
-h | --help | Show help and exit. |
-v | --version | Show the version number and exit. |
Indentation options
| Flag | Long form | Default | Description |
|---|
-s | --indent-size | 4 | Number of spaces per indentation level. |
-c | --indent-char | " " | Character used for indentation. |
-t | --indent-with-tabs | false | Indent with tabs, overrides -s and -c. |
-l | --indent-level | 0 | Initial indentation level. |
| --indent-empty-lines | false | Keep indentation on empty lines. |
| --editorconfig | false | Use EditorConfig to set up options from .editorconfig. |
| Flag | Long form | Default | Description |
|---|
-e | --eol | first newline in file, else \n | Line terminator character(s). |
-n | --end-with-newline | false | End output with a newline. |
-p | --preserve-newlines | true | Preserve existing line breaks. Use --no-preserve-newlines to disable. |
-m | --max-preserve-newlines | 10 | Maximum blank lines to preserve in one chunk. |
-w | --wrap-line-length | 0 | Wrap lines exceeding N characters. 0 disables wrapping. |
-b | --brace-style | collapse | Brace style: collapse, expand, end-expand, none. Append ,preserve-inline to keep single-line blocks. |
-C | --comma-first | false | Place commas at the start of new lines instead of the end. |
-O | --operator-position | before-newline | Operator position on wrapped lines: before-newline, after-newline, preserve-newline. |
| --templating | auto | Templating languages to recognize: auto, none, django, erb, handlebars, php, smarty, angular. |
Space options
| Flag | Long form | Default | Description |
|---|
-P | --space-in-paren | false | Add padding spaces inside parentheses: f( a, b ). |
-Q | --space-in-empty-paren | false | Add a space inside empty parentheses: f( ). |
-j | --jslint-happy | false | Enable JSLint-stricter mode. Implies --space-after-anon-function. |
-a | --space-after-anon-function | false | Add a space before anonymous function parens: function (). |
| --space-after-named-function | false | Add a space before named function parens: function example (). |
Method chaining
| Flag | Long form | Default | Description |
|---|
-u | --unindent-chained-methods | false | Do not indent chained method calls. |
-B | --break-chained-methods | false | Break chained method calls onto separate lines. |
Miscellaneous
| Flag | Long form | Default | Description |
|---|
-k | --keep-array-indentation | false | Preserve original array indentation. |
-x | --unescape-strings | false | Decode printable characters encoded in \xNN notation. |
-X | --e4x | false | Pass E4X XML literals through untouched. |
| --good-stuff | — | Enables --keep-array-indentation and --jslint-happy together. |
Examples
# Beautify from stdin to stdout (pipe to - filename)
echo 'function foo(){return 42;}' | js-beautify -
# Beautify a file, output to stdout
js-beautify app.js
# Beautify multiple files to stdout
js-beautify src/*.js
# Replace files in-place
js-beautify --replace src/main.js src/utils.js
# Write beautified output to a new file
js-beautify -o dist/formatted.js src/main.js
# Use 2-space indentation and end with a newline
js-beautify -s 2 -n app.js
# Indent with tabs, expand braces
js-beautify --indent-with-tabs --brace-style expand app.js
# Use a config file
js-beautify --config .jsbeautifyrc app.js
# Pipe from another tool
cat bundle.min.js | js-beautify - -s 2 > bundle.formatted.js
You can also use js-beautify --css or js-beautify --html as an alternative to the css-beautify and html-beautify commands. The --type flag selects the beautifier without filtering input files.
Configuration loading
The CLI resolves options from the following sources in priority order (highest to lowest):
- CLI flags passed directly
jsbeautify_-prefixed environment variables- A JSON config file specified via
--config
- A
.jsbeautifyrc JSON file found at or above the current working directory
Option names in .jsbeautifyrc use underscores instead of dashes, matching the library API names.