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    1.4.0 • Public • Published

    JS Beautifier

    Build Status NPM version

    Important Note:

    This is a copy of the original 1.4.0 repo ( created by Jon Schlinkert. This is only for archiving purposes.

    This little beautifier will reformat and reindent bookmarklets, ugly JavaScript, unpack scripts packed by Dean Edward’s popular packer, as well as deobfuscate scripts processed by


    You can beautify javascript using JS Beautifier in your web browser, or on the command-line using node.js or python.

    Web Browser

    Open Options are available via the UI.


    To beautify using python:

    $ pip install jsbeautifier
    $ js-beautify file.js

    Beautified output goes to stdout.

    To use jsbeautifier as a library is simple:

    import jsbeautifier
    res = jsbeautifier.beautify('your javascript string')
    res = jsbeautifier.beautify_file('some_file.js')

    ...or, to specify some options:

    opts = jsbeautifier.default_options()
    opts.indent_size = 2
    res = jsbeautifier.beautify('some javascript'opts)


    As an alternative to the Python script, you may install the NPM package js-beautify. When installed globally, it provides an executable js-beautify script. As with the Python script, the beautified result is sent to stdout unless otherwise configured.

    $ npm -g install js-beautify
    $ js-beautify foo.js

    You can also use js-beautify as a node library (install locally, the npm default):

    $ npm install js-beautify
    var beautify = require('js-beautify').js_beautify,
        fs = require('fs');
    fs.readFile('foo.js', 'utf8', function (err, data) {
        if (err) {
            throw err;
        console.log(beautify(data, { indent_size: 2 }));


    These are the command-line flags for both Python and JS scripts:

    CLI Options:
      -f, --file       Input file(s) (Pass '-' for stdin)
      -r, --replace    Write output in-place, replacing input
      -o, --outfile    Write output to file (default stdout)
      --config         Path to config file
      --type           [js|css|html] ["js"]
      -q, --quiet      Suppress logging to stdout
      -h, --help       Show this help
      -v, --version    Show the version
    Beautifier Options:
      -s, --indent-size             Indentation size [4]
      -c, --indent-char             Indentation character [" "]
      -l, --indent-level            Initial indentation level [0]
      -t, --indent-with-tabs        Indent with tabs, overrides -s and -c
      -p, --preserve-newlines       Preserve line-breaks (--no-preserve-newlines disables)
      -m, --max-preserve-newlines   Number of line-breaks to be preserved in one chunk [10]
      -P, --space-in-paren          Add padding spaces within paren, ie. f( a, b )
      -j, --jslint-happy            Enable jslint-stricter mode
      -b, --brace-style             [collapse|expand|end-expand] ["collapse"]
      -B, --break-chained-methods   Break chained method calls across subsequent lines
      -k, --keep-array-indentation  Preserve array indentation
      -x, --unescape-strings        Decode printable characters encoded in xNN notation
      -w, --wrap-line-length        Wrap lines at next opportunity after N characters [0]
      -X, --e4x                     Pass E4X xml literals through untouched
      --good-stuff                  Warm the cockles of Crockford's heart

    These largely correspond to the underscored option keys for both library interfaces, which have these defaults:

        "indent_size": 4,
        "indent_char": " ",
        "indent_level": 0,
        "indent_with_tabs": false,
        "preserve_newlines": true,
        "max_preserve_newlines": 10,
        "jslint_happy": false,
        "brace_style": "collapse",
        "keep_array_indentation": false,
        "keep_function_indentation": false,
        "space_before_conditional": true,
        "break_chained_methods": false,
        "eval_code": false,
        "unescape_strings": false,
        "wrap_line_length": 0

    In addition to CLI arguments, you may pass config to the JS executable via:

    • any jsbeautify_-prefixed environment variables
    • a JSON-formatted file indicated by the --config parameter
    • a .jsbeautifyrc file containing JSON data at any level of the filesystem above $PWD

    Configuration sources provided earlier in this stack will override later ones.

    You might notice that the CLI options and defaults hash aren't 100% correlated. Historically, the Python and JS APIs have not been 100% identical. For example, space_before_conditional is currently JS-only, and not addressable from the CLI script. There are a few other additional cases keeping us from 100% API-compatibility. Patches welcome!

    CSS & HTML

    In addition to the js-beautify executable, css-beautify and html-beautify are also provided as an easy interface into those scripts. Alternatively, js-beautify --css or js-beautify --html will accomplish the same thing, respectively.

    // Programmatic access
    var beautify_js = require('js-beautify'); // also available under "js" export
    var beautify_css = require('js-beautify').css;
    var beautify_html = require('js-beautify').html;
    // All methods accept two arguments, the string to be beautified, and an options object.

    The CSS & HTML beautifiers are much simpler in scope, and possess far fewer options.

    CSS Beautifier Options:
      -s, --indent-size             Indentation size [4]
      -c, --indent-char             Indentation character [" "]
    HTML Beautifier Options:
      -I, --indent-inner-html       Indent <head> and <body> sections. Default is false.
      -s, --indent-size             Indentation size [4]
      -c, --indent-char             Indentation character [" "]
      -b, --brace-style             [collapse|expand|end-expand] ["collapse"]
      -S, --indent-scripts          [keep|separate|normal] ["normal"]
      -w, --wrap-line-length        Maximum characters per line (0 disables) [250]
      -p, --preserve-newlines       Preserve existing line-breaks (--no-preserve-newlines disables)
      -m, --max-preserve-newlines   Maximum number of line-breaks to be preserved in one chunk [10]
      -U, --unformatted             List of tags (defaults to inline) that should not be reformatted


    You are free to use this in any way you want, in case you find this useful or working for you but you must keep the copyright notice and license. (MIT)


    Thanks also to Jason Diamond, Patrick Hof, Nochum Sossonko, Andreas Schneider, Dave Vasilevsky, Vital Batmanov, Ron Baldwin, Gabriel Harrison, Chris J. Shull, Mathias Bynens, Vittorio Gambaletta and others. js-beautify@1.3.4




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