# rollup-starter-lib [](https://greenkeeper.io/) 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](https://github.com/zeit/ms) package: ```js console.log("it will be lunchtime in " + howLongTillLunch()); ``` ## Getting started Clone this repository and install its dependencies: ```bash 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 `require`s 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 `import`s 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 `