ycp-rollup-starter-lib

1.0.16 verified Mon Apr 27 auth: no javascript

A bare-bones example repository demonstrating how to create a JavaScript library using Rollup, including importing a CommonJS module from node_modules. The library 'how-long-till-lunch' uses the 'ms' package to calculate time until lunch. This is a starter template, not a standalone library; version 1.0.16 is active but has no maintainer activity. Key differentiators: it provides CommonJS, ES module, and UMD builds via Rollup, with variations for Babel or Bublé transpilation. Not intended for production use as a dependency.

Common errors

error Error: Cannot find module 'ms' ↓

cause The 'ms' package is installed as a devDependency but your code uses it at runtime. Running the built library outside the project directory fails.

fix

Run npm install --save ms to add it as a runtime dependency, or ensure you run your application from within the project directory.

error npm ERR! code ELIFECYCLE ↓

cause Build script fails due to missing rollup or other dev dependencies.

fix

Run npm install before npm run build.

error SyntaxError: Unexpected token 'export' ↓

cause Trying to run the ES module file directly with older Node.js versions (<13) without ESM support.

fix

Use Node.js version 13 or later with --experimental-modules flag, or use the CommonJS bundle instead.

Warnings

gotcha This package is a starter template, not a published library. Do not install it as a dependency (npm install ycp-rollup-starter-lib) expecting a usable library. ↓

fix Clone the GitHub repo instead: git clone https://github.com/rollup/rollup-starter-lib.git

deprecated The Greenkeeper badge is outdated. Greenkeeper was acquired by Snyk and the service changed. ↓

fix Consider using Dependabot or Renovate for dependency updates.

gotcha The 'ms' dependency is a devDependency in the starter, but the example imports it as if it were a runtime dependency. This may confuse beginners. ↓

fix If you use the starter as a base for your own library, move 'ms' to dependencies if your library uses it at runtime.

Install

npm install ycp-rollup-starter-lib

yarn add ycp-rollup-starter-lib

pnpm add ycp-rollup-starter-lib

Imports

default

import howLongTillLunch from './how-long-till-lunch';

The library exports a default function.

require

wrong

const howLongTillLunch = require('how-long-till-lunch');

correct

const howLongTillLunch = require('./how-long-till-lunch.cjs.js');

Use the CommonJS file path for Node.js require.

script tag
```
<script src="dist/how-long-till-lunch.umd.js"></script>
```
The UMD build exposes the library as a global variable.

Quickstart

Shows how to clone, build, and use the example library with ES module import syntax, demonstrating the standard workflow for this starter.

// Clone and build the library
git clone https://github.com/rollup/rollup-starter-lib.git
cd rollup-starter-lib
npm install
npm run build

// Create a test file: test.mjs
import howLongTillLunch from './dist/how-long-till-lunch.esm.js';
console.log('Lunch in:', howLongTillLunch());

// Run with node
node test.mjs