This repo contains a bare-bones example of how to create a library using Rollup, including importing a module from node_modules and converting it from CommonJS.

We're creating a library called how-long-till-lunch, which usefully tells us how long we have to wait until lunch, using the ms package:

console.log('it will be lunchtime in ' + howLongTillLunch());

Clone this repository and install its dependencies:

git clone https://github.com/rollup/rollup-starter-lib
cd rollup-starter-lib
npm install

npm run build builds the library to dist, generating three files:

• dist/how-long-till-lunch.cjs.js A CommonJS bundle, suitable for use in Node.js, that requires the external dependency. This corresponds to the "main" field in package.json
• dist/how-long-till-lunch.esm.js an ES module bundle, suitable for use in other people's libraries and applications, that imports the external dependency. This corresponds to the "module" field in package.json
• dist/how-long-till-lunch.umd.js a UMD build, suitable for use in any environment (including the browser, as a <script> tag), that includes the external dependency. This corresponds to the "browser" field in package.json

npm run dev builds the library, then keeps rebuilding it whenever the source files change using rollup-watch.

npm test builds the library, then tests it.

• babel — illustrates writing the source code in ES2015 and transpiling it for older environments with Babel
• buble — similar, but using Bublé which is a faster alternative with less configuration
• TypeScript — uses TypeScript for type-safe code and transpiling

MIT.