This project illustrates how a library written in es6 can be published supporting tree shaking. I intentionally created a minimal React component library as it involves some extra configuration than a simple tiny module.

The library in the src directory is written in es6 using the import and export syntax. The project that uses this library can be found in the test directory.

The library is bundled with rollup. The rollup configuration uses babel to create an es module using the import and export syntax.

The project is bundled with webpack as it is meant to run as a stand-alone application in the browser. The webpack configuration has a specific optimization configuration to create separate bundles for vendor libraries and webpack runtime code. This optimization configuration is not needed, and it is only used in this case to isolate the code that is produced for the index.js file.

Clone the project and install and build the library:

yarn install && yarn build

Then navigate to the test directory and install and build the project:

cd test && yarn install && yarn build

Notice that the webpack output will contain something like the following:

index.js  221 bytes       0  [emitted]  index

Now if we import and use the Input component in ./test/src/index:

import React from 'react';
import { render } from 'react-dom';
import { Button, Input } from 'es6-lib';

render(
  <div>
    <Button />
    <Input />
  </div>,
  document.getElementById('root')
);

and run yarn build again, we'll notice that the size of the index.js file increased.

index.js  279 bytes       0  [emitted]  index

That is because webpack now imported the code for the Input component as well. In the previous build, webpack didn't include the code for the Input component from the es6-lib package, as we were not using it.