Welcome

What Does A React Library Development Environment Look Like?

Introduction

Essential Files and Directories for Publishing a React Library

An Introduction to the 3 Types of Dependencies in React Libraries

Installing React and React-DOM as peerDependencies

A Beginner's Guide to Using Git to Push Code to GitHub

Initialize

Scroller schema

Implementing Scroller

How to Set Up Storybook to View and Test Code

Implement

Setting Up ESBuild to Simplify Code Maintainability

A Brief Guide to JavaScript Modules and What They Do

How to Use ESBuild to Export Multiple JavaScript Module Formats

How to Configure and Publish an NPM Package

Deploy

What it Takes to Make Your React Library More Maintainable

3 Ways to Add Typescript to a React Library

How to Install Jest and Run Your First Unit Test

How to Install and Run ESLint When Creating React Libraries

How to Prevent Bad Git Commits with Lint-staged

Maintain

Course Wrap Up - Creating React Libraries from Scratch

Summary

esbuild

react

In this course, we'll cover what it takes to write, maintain, and publish a React library from scratch. 
In the 2020 State of JS survey, an annual survey conducted of the frontend JavaScript community, React came in as the most used framework for frontend development. Because React is so popular, building libraries in it can open you up to a wide range of users, contributors, and possibilities!

## Why this course

Building a library is so much more than just the code. 
We need to know the ins and outs of versioning, deploying, building, documenting, dependency management, module types, tooling, and more. 
This is a daunting task for just one tutorial to cover. Creating React Libraries from Scratch will teach you everything you need to know to succeed in creating a library.

Don't worry if you're not a React wizard. This course is designed for beginner/intermediate developers who have never deployed a library before and have minimal React experience. However, you should be familiar with JavaScript.

## Course Topics
 
Throughout Creating React Libraries from Scratch we'll develop a React Hook called Scroller that will provide a utility for scrolling around web pages—taking advantage of window.scrollTo. 
We'll start in module 1 with an empty directory; adding documentation files, installing dependencies, and setting up GitHub. Right away, you'll have a project that could be deployable as a fully functional library!
In module 2 we'll implement scroller while taking advantage of Storybook to visually test our code. By module 3 Scroller will be deployed to npm in multiple JavaScript module formats.
Finally, in module 4, we'll look at different tools and techniques in software development to maintain a library. This includes linting, unit tests, TypeScript, and Lint-Staged!
By the end of this course, you'll be able to run _npm install scroller_, and take advantage of React code __you__ wrote in future projects.

Creating React Libraries from Scratch will dive into:
- initializing a new npm package
- maintaining code quality
- publishing to npm
- keeping contributors on track
- exposing modules that work in NodeJS and the Web
- unit-testing
- Storybook for demoing components
- exposing typing using TypeScript
- and more!

In this course we'll cover what it takes to maintain, write, and publish a React library from scratch.

Creating React Libraries from Scratch

Creating a React library from `yarn init` to deployed on npm

The different types of JavaScript dependency types and versioning

Setting up documentation for contributers and consumers

Keeping up with code quality while multiple people work on a project

There are cases when we want to export multiple module types.
Scroller will expose CJS and ESM module formats.
This allows consumers of Scroller to use older versions of NodeJS to import the CJS build, or newer NodeJS versions to import ESM. When Scroller is used directly in the browser, users can use the ESM build.

 script that runs ESBuild's CLI. To achieve multiple builds we'll create a NodeJS build script called 

At the root of our Scroller project, create a new file called 

 function using similar parameters to our build 

const esbuild = require("esbuild");

esbuild.build({
  entryPoints: ["src/index.js"],
  bundle: true,
  format: "esm",
  outdir: "./dist",
});

 to enable ESM modules.
To avoid having to configure NodeJS, we'll stick to CJS for any build tool configuration.
The code above will look similar to our 

esbuild ./src/index.js --bundle --format=esm --outdir=dist

We tell ESBuild to build our code found at 

 as an ESM module, then put the bundled code into a 

---
title: How to Use ESBuild to Export Multiple JavaScript Module Formats
slug: building-multiple-modules
description: Updating ESBuild to export multiple JS module formats.
privateVideoUrl: https://fullstack.wistia.com/medias/7h202ztbyl
useMdx: true
isPublicLesson: false
---

import { Quiz } from "~/../components/quiz";
import { Directory, Folder, File } from "~/../components/directory";

There are cases when we want to export multiple module types.
Scroller will expose CJS and ESM module formats.
This allows consumers of Scroller to use older versions of NodeJS to import the CJS build, or newer NodeJS versions to import ESM. When Scroller is used directly in the browser, users can use the ESM build.

## Setting up ESBuild with JavaScript

We first set up ESBuild using a `package.json` script that runs ESBuild's CLI. To achieve multiple builds we'll create a NodeJS build script called `esbuild.js`.

At the root of our Scroller project, create a new file called `esbuild.js`.

![An image showing an esbuild build file created in the Scroller directory.](https://d2uusema5elisf.cloudfront.net/courses/creating-react-libraries-from-scratch/module_04/lesson_03/public/esbuild-create.png)

Inside `esbuild.js` import the ESBuild library using CJS `require()` syntax.
Call the `build` function using similar parameters to our build `package.json` script.

```js { actualFilename=./protected/esbuild.first.js endChar=143 endLine=9 startChar=0 startLine=1 statedFilename=esbuild.js url=https&#x3A;//gitlab.com/fullstackio/books/creating-react-libraries-from-scratch/module_04/lesson_03/protected/esbuild.first.js }
const esbuild = require("esbuild");

esbuild.build({
  entryPoints: ["src/index.js"],
  bundle: true,
  format: "esm",
  outdir: "./dist",
});
```

NodeJS requires files to use the `.mjs` extension, or update parameters in `package.json` to enable ESM modules.
To avoid having to configure NodeJS, we'll stick to CJS for any build tool configuration.
The code above will look similar to our `package.json` build script (`esbuild ./src/index.js --bundle --format=esm --outdir=dist`).

We tell ESBuild to build our code found at `src/index.js` as an ESM module, then put the bundled code into a `dist` directory.

Updating ESBuild to export multiple JS module formats.

Learn

The newline Guide to Building Your First GraphQL Server with Node and TypeScript

Teach

Amelia Wattenberger

Author of Fullstack D3

Community

Creating React Libraries from Scratch

Module 1: Introduction

Introduction:

Start Here

Introduction: (2:16)

Welcome

Introduction: (2:25)

What Does A React Library Development Environment Look Like?

Module 2: Initialize

Lesson 1: (5:25)

Essential Files and Directories for Publishing a React Library

Lesson 2: (4:36)

An Introduction to the 3 Types of Dependencies in React Libraries

Lesson 3: (3:07)

Installing React and React-DOM as peerDependencies

Lesson 4: (5:11)

A Beginner's Guide to Using Git to Push Code to GitHub

Module 3: Implement

Lesson 1: (1:07)

Scroller schema

Lesson 2: (2:52)

Implementing Scroller

Lesson 3: (3:56)

How to Set Up Storybook to View and Test Code

Module 4: Deploy

Lesson 1: (2:18)

Setting Up ESBuild to Simplify Code Maintainability

Lesson 2: (4:54)

A Brief Guide to JavaScript Modules and What They Do

Lesson 3: (2:54)

How to Use ESBuild to Export Multiple JavaScript Module Formats

Lesson 4: (5:34)

How to Configure and Publish an NPM Package

Module 5: Maintain

Lesson 1: (0:43)

What it Takes to Make Your React Library More Maintainable

Lesson 2: (7:01)

3 Ways to Add Typescript to a React Library

Lesson 3: (4:33)

How to Install Jest and Run Your First Unit Test

Lesson 4: (4:33)

How to Install and Run ESLint When Creating React Libraries

Lesson 5: (2:23)

How to Prevent Bad Git Commits with Lint-staged

Module 6: Summary

Lesson 1: (0:34)

Course Wrap Up - Creating React Libraries from Scratch

How to Use ESBuild to Export Multiple JavaScript Module Formats