6to5 turns ES6 code into vanilla ES5, so you can use ES6 features today.

• Fast - 10x faster than Traceur.
• Extensive - with Browserify support, Node API, Connect Middleware and a CLI.
• Lossless - source map support so you can debug your compiled code with ease.
• Compact - maps directly to the equivalent ES5 with no runtime required.
• Concise - does not pollute scope with unneccesary variables.

Features

Name	Implemented
Arrow functions	✓
Classes	✓
Default parameters	✓
Spread	✓
Block binding	✓
Property method assignment	✓
Rest parameters	✓
Template literals	✓
Modules	✓
Property name shorthand	✓
Computed property names	✓
Constants	✓
Binary and Octal Literals	✓
For-of	✓
Array comprehension	✓
Destructuring	✓
Generators

Installation

$ npm install -g 6to5

Usage

CLI

Compile the file script.js and output it to script-compiled.js.

$ 6to5 script.js -o script-compiled.js

Compile the entire src directory and output it to the lib directory.

$ 6to5 src -d lib

Compile the file script.js and output it to stdout.

$ 6to5 script.js

Browserify

$ browserify script.js -t 6to5/browserify --outfile bundle.js

Node

var to5 = require("6to5");

to5.transform("code();");

to5.transformFileSync("script.js");

to5.transformFile("script.js", function (err, data) {

});

Options

to5.transform("code();", {
  // List of transformers to EXCLUDE
  // This is a camelised version of the name found in `features`
  // eg. "Arrow functions" is "arrowFunctions"
  blacklist: [],

  // List of transformers to ONLY use.
  // See `blacklist` for naming scheme.
  whitelist: [],

  // Append source map and comment to bottom of returned output.
  sourceMap: false,

  // Filename for use in errors etc.
  filename: "unknown",

  // Format options
  // See https://github.com/Constellation/escodegen/wiki/API for options.
  format: {}
});

Require hook

All subsequent files required by node will be transformed into ES5 compatible code.

require("6to5/register");

Connect Middleware

var to5 = require("6to5");

app.use(to5.middleware({
  options: {
    // options to use when transforming files
  },
  src: "assets",
  dest: "cache"
}));

app.use(connect.static("cache"));

Browserify

var to5 = require("6to5");
browserify()
  .transform(to5.browserify)
  .require("script.js", { entry: true })
  .bundle({ debug: true })
  .pipe(fs.createWriteStream("bundle.js"));

Caveats

For-of

Classes

Cannot subclass built-ins such as Date, Array, DOM etc.

Generator comprehension

Not supported.

Comparison to Traceur

Performance