MattMS / decaffeinate

Goodbye CoffeeScript, hello JavaScript!

decaffeinate

Goodbye CoffeeScript, hello JavaScript!

JavaScript is the future, in part thanks to CoffeeScript. Now that it has served its purpose, it's time to move on. Convert your CoffeeScript source to modern JavaScript with decaffeinate.

Installation and usage

$ npm install -g decaffeinate
$ decaffeinate input.coffee
input.coffee → input.js

Alternatively, paste code into the online repl to immediately see the output.

For real-world use cases, you'll likely want to spend some time understanding the different options and nuances of the decaffeinate tool. You'll also likely want to run decaffeinate using the bulk-decaffeinate wrapper tool, or write your own wrapper script. See the Conversion Guide for more information and advice on running decaffeinate on real-world code.

Status

Mostly complete. The project has been used to convert tens of thousands of lines of production code, and can be relied upon for production use, but no guarantees are made. For small projects like hubot and autoprefixer, decaffeinate can convert all code to JavaScript with all tests passing. For larger projects, there may be some files that fail to convert or cases where the generated JS has correctness issues.

Check the issues page for outstanding bugs and incomplete features. And, of course, you're welcome to file issues for any problems you run into.

Goals

• Fully automated conversion of the CoffeeScript language to modern JavaScript.
• Preserve whitespace, formatting, and comments as much as possible to allow a full one-time conversion of your CoffeeScript source code.
• Focus on correctness as the first priority, with some options to generate nicer code at the expense of 100% correctness.
• Provide helpful error messages when it encounters an unsupported language construct.

Options

• --keep-commonjs: Do not convert require and module.exports to import and export.
• --prefer-const: Use const when possible in output code.
• --loose-default-params: Convert CS default params to JS default params.
• --loose-for-expressions: Do not wrap expression loop targets in Array.from.
• --loose-for-of: Do not wrap JS for...of loop targets in Array.from.
• --loose-includes: Do not wrap in Array.from when converting in to includes.
• --allow-invalid-constructors: Don't error when constructors use this before super or omit the super call in a subclass.
• --enable-babel-constructor-workaround: Use a hacky babel-specific workaround to allow this before super in constructors.

For more usage details, see the output of decaffeinate --help.