One of the ways you can use Ruby2JS is through the require hook. The require hook will bind itself to node's require and automatically compile files on the fly. This is equivalent to Babel's @babel/register.

Install

npm install @ruby2js/register --save-dev

Usage

require("@ruby2js/register");

All subsequent files required by node with the extensions .rb will be transformed by Ruby2JS.

NOTE: all requires to node_modules will be ignored.

Specifying options

require("@ruby2js/register")({
  // Ruby2JS options
  options: {
    eslevel: 2021,
    autoexports: 'default',
    filters: ['cjs', 'functions']
  },

  // Array of ignore conditions, either a regex or a function. (Optional)
  // File paths that match any condition are not compiled.
  ignore: [
    // When a file path matches this regex then it is **not** compiled
    /regex/,

    // The file's path is also passed to any ignore functions. It will
    // **not** be compiled if `true` is returned.
    function(filepath) {
      return filepath !== "/path/to/ruby-file.rb";
    },
  ],

  // Array of accept conditions, either a regex or a function. (Optional)
  // File paths that match all conditions are compiled.
  only: [
    // File paths that **don't** match this regex are not compiled
    /my_ruby_folder/,

    // File paths that **do not** return true are not compiled
    function(filepath) {
      return filepath === "/path/to/ruby-file.rb";
    },
  ],

  // Setting this will remove the currently hooked extensions of `.rb`
  // so you'll have to it them back if you want it to be used
  // again.
  extensions: [".rb"],
});

Notes:

• No caching is provided at this time.

• This code uses the same require hook that Babel uses, so the same caveats and limitations apply. In particular, @ruby2js/register does not support compiling native Node.js ES modules on the fly, since currently there is no stable API for intercepting ES modules loading.