6to5-loader

6to5-loader

Turn ES6 code into vanilla ES5 with no runtime required using 6to5;

Notes: Issues with the output should be reported on the 6to5 issue tracker;

Install

$ npm install --save-dev 6to5-loader

Usage

import Animal from '6to5!./Animal.js';

class Person extends Animal {
  constructor(arg='default') {
    this.eat = 'Happy Meal';
  }
}

export default Person;

var Person = require('6to5!./Person.js').default;
new Person();

Or within the webpack config:

module: {
    loaders: [
        { test: /\.js$/, exclude: /node_modules/, loader: '6to5-loader'}
    ]
}

and then import normally:

import Person from './Person.js';

Troubleshooting

6to5-loader is slow!

Make sure you are transforming as few files as possible. Because you are probably matching /\.js$/, you might be transforming the node_modules folder or other unwanted source. See the exclude option in the loaders config as documented above.

6to5 is injecting a runtime into each file and bloating my code!

6to5 uses a very small runtime for common functions such as _extend. By default this will be added to every file that requires it.

You can instead require the 6to5 runtime as a separate module to avoid the duplication.

The following configuration disables automatic per-file runtime injection in 6to5, instead bundling a single runtime and providing it to each transformed file.

loaders: [
  // runtime=true tells 6to5 to expect a runtime, but we still need to bundle it.
  {test: /\.jsx?$/, exclude: /node_modules/, loader: '6to5-loader?experimental=true&runtime=true'}
],
plugins: [
  // to5Runtime wants to export to the window. This loader grabs the export
  // and instead provides it to the modules that need it.
  // 
  // The 'imports?global=>{}!' is optional, but prevents to5Runtime from leaking
  // to the window object.
  // 
  // Alternatively, write `require('6to5/runtime')` at the top of your entry point.
  // Leaks the object to the window, but it's simple.
  new webpack.ProvidePlugin({
    to5Runtime: "imports?global=>{}!exports-loader?global.to5Runtime!6to5/runtime"
  })
]

This can save significant overhead if you use 6to5 in many modules.

Options

See the 6to5 options

License

MIT © Luis Couto