For formatting, searching, and rewriting JavaScript. Analogous to gofmt.

npm install -g jsfmt

$ jsfmt --help
Usage:
  jsfmt [--no-format] [--diff|--list|--write] [--rewrite PATTERN|--search PATTERN] [<file>...]
  jsfmt (--version | --help)

Options:
  -h --help                      Show this help text
  -v --version                   Show jsfmt version
  -d --diff                      Show diff against original file
  -l --list                      List the files which differ from jsfmt output
  --no-format                    Do not format the input file(s)
  -w --write                     Overwrite the original file with jsfmt output
  -r=PATTERN --rewrite PATTERN   Rewrite rule (e.g., 'a.slice(b, len(a) -> a.slice(b)')
  -s=PATTERN --search PATTERN    Search rule (e.g., 'a.slice')

If no path is given it will read from stdin. A directory path will recurse over all *.js files in the directory.

For formatting jsfmt uses esformatter.

Any of the esformatter formatting options can be overwritten via a .jsfmtrc file. The file is parsed using rc, which accepts either a json or ini formatted file.

jsfmt will also attempt to pickup and use the configured indent variable from your .jshintrc configuration file, if present.

A config file can be manually specified using --config config.json.

The --rewrite flag allows rewriting portions of the JavaScript's AST before formatting. This is especially handy for intelligent renaming and handling API changes from a library. The rewrite rule must be a string of the form:

pattern -> replacement

Both pattern and replacement must be valid JavaScript. In pattern, single-character lowercase identifiers serve as wildcards matching arbitrary expressions; those expressions will be substituted for the same identifiers in the replacement.

Rewrite occurences of _.reduce to use native reduce:

jsfmt --rewrite "_.reduce(a, b, c) -> a.reduce(b, c)" reduce.js

The --search flag allows searching through a JavaScript's AST. The search rule is very similar to the rewrite rule but just outputs expressions that match the given search expression. The search expression must be valid JavaScript.

Find occurences of _.reduce:

jsfmt --search "_.reduce(a, b, c)" reduce.js

The --validate flag will print any errors found by esprima while parsing the JavaScript.

jsfmt --validate bad.js

jsfmt.format(<javascript_string>, <config_object>) // Returns formatted JavaScript

var config = jsfmt.getConfig(); // Loads the jsfmt config from the appropriate rc file or default config object

var jsfmt = require('jsfmt');
var fs = require('fs');

var js = fs.readFileSync('unformatted.js');
var config = jsfmt.getConfig();

js = jsfmt.format(js, config);

jsfmt.rewrite(<javascript_string>, <rewrite_rule>) // Returns rewritten JavaScript

var jsfmt = require('jsfmt');
var fs = require('fs');

var js = fs.readFileSync('each.js');

js = jsfmt.rewrite(js, "_.each(a, b) -> a.forEach(b)");

jsfmt.search(<javascript_string>, <search_expression>) // Returns array of matches

var jsfmt = require('jsfmt');
var fs = require('fs');

var js = fs.readFileSync('component.js');

jsfmt.search(js, "R.Component.create(a, { dependencies: z })").forEach(function(matches, wildcards) {
  console.log(wildcards.z);
});

jsfmt.validate(<javascript_string>) // Returns errors found while parsing JavaScript

var jsfmt = require('jsfmt');
var fs = require('fs');

var js = fs.readFileSync('each.js');
var errors = jsfmt.validate(js);

for (var i = 0; i < errors.length; i++) {
  console.error(errors[i]);
}

• Atom Package - https://atom.io/packages/atom-jsfmt - "Automatically run jsfmt every time you save a JavaScript source file."
• Grunt Task - https://github.com/james2doyle/grunt-jsfmt - "A task for the jsfmt library."
• Emacs Plugin - https://github.com/brettlangdon/jsfmt.el - "Run jsfmt from within emacs"

• Fixed bug when searching for expressions within BlockStatement or Program body
• Added JSON support

• Added CONTRIBUTING
• Added tests
• Added Gruntfile for development
• Added CI support
• Added style guide
• Added default formatting config
• Exposed jsfmt.getConfig api method for loading jsfmt config
• Exposed jsfmt.format(js[, options]) api method for formatting
• Added --validate option and exposed jsfmt.validate api method
• Pinned dependencies

• Add rc and --config config.json support for formatting configuration
• Making --format the default action
• Fix support for shebang at the top of js files, e.g. #!/usr/bin/env node
• Fix jsfmt diff mode where whitespace was unaccounted for due to -b git diff option

• Initial release

Apache License, Version 2.0. Copyright 2014 Rdio, Inc.