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

Writing our whole library in a single file makes it hard to find code, and vastly increases the chances of merge conflicts in Git. The next step is to separate code into separate files to improve maintainability and readability. In the early days of JavaScript having separate files meant we needed to have multiple script tags like 

 in our HTML to import each file. This was tedious because a new script tag would need to be added for each new file created. Another issue is some files are dependent on other files. So a function in file X would need to exist before it was called in file Y. Not only did we have to create new 

 tags for each new file, but the files had to the ordered correctly!

These issues lead to new module systems being introduced into the JavaScript community, such as 

 (ECMAScript Modules) introduced as a core JavaScript feature and final standard for modules.

CommonJS (CJS) modules were created to provide 

 module handling in NodeJS. When a file needs to make code public, the CJS uses 

 syntax. For example, if we were to export an 

// add.js
function add(a, b) {
  return a + b;
}

module.exports = add;

// anotherFile.js
const add = require("./add");

CJS is still heavily used in NodeJS programs, and while running code in NodeJS environments. For example, many build tools like Webpack (the 

Asynchronous Module Definition (AMD) is a solution for loading dependencies asynchronously, which was popularized in a library called RequireJS. Code using AMD would look like:

define(["react", "react-dom"], function(react, reactDOM) {
  reactDOM.render(..., ...);
});

---
title: A Brief Guide to JavaScript Modules and What They Do
slug: what-are-js-modules
description: What are JS Modules, and how do they affect consumers of our code?
privateVideoUrl: https://fullstack.wistia.com/medias/fgxxkms0da
isPublicLesson: false
useMdx: true
---

import { Quiz } from "~/../components/quiz";

Writing our whole library in a single file makes it hard to find code, and vastly increases the chances of merge conflicts in Git. The next step is to separate code into separate files to improve maintainability and readability. In the early days of JavaScript having separate files meant we needed to have multiple script tags like `<script src="myFile.js"></script>` in our HTML to import each file. This was tedious because a new script tag would need to be added for each new file created. Another issue is some files are dependent on other files. So a function in file X would need to exist before it was called in file Y. Not only did we have to create new `<script>` tags for each new file, but the files had to the ordered correctly!

These issues lead to new module systems being introduced into the JavaScript community, such as **AMD** (Asynchronous Module Definition) and **CJS** (CommonJS). Only recently was **ESM** (ECMAScript Modules) introduced as a core JavaScript feature and final standard for modules.

### CJS (CommonJS)

CommonJS (CJS) modules were created to provide **synchronous** module handling in NodeJS. When a file needs to make code public, the CJS uses `module.exports` syntax. For example, if we were to export an `add(a, b);` function using CJS it would look like:

```javascript
// add.js
function add(a, b) {
  return a + b;
}

module.exports = add;
```

Importing code uses the `require()` syntax. To use `add()` in a separate file we use `require()` to point to the `add.js` file.

```javascript
// anotherFile.js
const add = require("./add");
```

CJS is still heavily used in NodeJS programs, and while running code in NodeJS environments. For example, many build tools like Webpack (the `webpack.config.js` file) use `module.exports` syntax to define configuration files.

### AMD (Asynchronous Module Definition)

Asynchronous Module Definition (AMD) is a solution for loading dependencies asynchronously, which was popularized in a library called RequireJS. Code using AMD would look like:

```javascript
define(["react", "react-dom"], function(react, reactDOM) {
  reactDOM.render(..., ...);
});
```

`define()` is a function that takes an array of dependencies as the first argument. The second argument is a callback, a function called after the dependencies are loaded, that provides access to the loaded modules. AMD is used less as ECMAScript Modules and Universal Module Definition have become more popular, but as a library owner, it's important to be aware of it.

What are JS Modules, and how do they affect consumers of our code?

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

A Brief Guide to JavaScript Modules and What They Do