Simple boilerplate for JavaScript libraries

Included with this boilerplate

• Eslint and prettier config
• Build scripts that output ESM, CJS and browser standalone. Write your code in ESM, export it anywhere
• As parcel does support TypeScript (among other stuff) out of the box, this library boilerplate does also support TypeScript.

How to use

• Clone this repo
• Update relevant information (license, author, ...) in the package.json
• Write your code in ./src. You can also change the exports in the index.* files to match your needs.
• You are good to publish

How to build and publish

• npm run build to build your library
• npm publish to publish it on NPM
• There is also a npm run watch script that will watch and rebuild for local development.

What is in the build

• ./dist/index.cjs and ./dist/index.mjs respectively contains CJS and ESM build. The host environment should be able to pick the right build automatically.
• ./dist/index.browser.js provide a static build for web-browsers. It exposes you library on the global object. It also packages all the required modules from the node_modules

How to import the lib

• CJS

const myLib = require("myLib");

// OR (depends on how you export the lib in index.cjs)

const { foo, bar } = require("myLib");

• ESM

import myLib from "myLib";

// OR (depends on how you export the lib in index.mjs)

import { foo, bar } from "myLib"

• Browser

<script src="myLib.js"></script>
<script>
  myLib.foo();
  
  // OR
  
  myLib();
</script>

Known issues

• No babel config is provided. Parcel does already ensure compatibility via the browserList key in the package.json. But it should be easy to add any required babel config see parcel doc
• Host using a Node version prior to 12.17.0 may have troubles finding the right module system as they do not recognise the exports key in the package.json. As Node 12.x has reached EOL in April 2022, I decided this is a non-issue even if easily fixable.