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

Linters are used to analyze our source code to find common bugs, keep coding styles consistent, and ensure we're using good practices. ESLint is the most popular linter in the JavaScript community. In this lesson, we'll take a look at implementing an ESLint configuration and running linting.

ESLint can be installed as a devDependency by running 

. ESLint comes with a nice initialization script to get started. Run 

We'll be asked a bunch of questions about our project. For Scroller we can use the following settings:

 will be created, which contains our configuration for ESLint.

 directory (we need to escape the double quotes because your terminal will try to resolve the glob 

 we ignore the terminal's glob resolution and use NodeJS's instead).

  "scripts": {
    "build": "node esbuild.js && tsc",
    "test": "jest",
    "lint": "eslint \"src/*\"",
    "storybook": "start-storybook -p 6006",
    "build-storybook": "build-storybook"
  },

 provided a couple of default rule sets. The first is 

, the recommended linting rules for React, and 

 which is a popular code standard for JavaScript.

 configuration enforces single quotes when creating strings 

, but we've been using double quotes in Scroller 

 file, add a rule to create an error if we don't use double-quotes. Rules we specify will overwrite the default rules given from the extended configurations.

  rules: {
    quotes: ["error", "double"],
  },

We also can turn rules off by adding rules with an 

 value. Override a few of airbnb's configurations to match our style.

---
title: How to Install and Run ESLint When Creating React Libraries
slug: eslint
description: Code linting and ensuring code style.
privateVideoUrl: https://fullstack.wistia.com/medias/qjv3o6c3fl
isPublicLesson: false
---

:::note
ESLint can be found at [https://eslint.org](https://eslint.org/).
:::

Linters are used to analyze our source code to find common bugs, keep coding styles consistent, and ensure we're using good practices. ESLint is the most popular linter in the JavaScript community. In this lesson, we'll take a look at implementing an ESLint configuration and running linting.

## Installing ESLint

ESLint can be installed as a devDependency by running `yarn add eslint --dev`. ESLint comes with a nice initialization script to get started. Run `yarn eslint --init`.

We'll be asked a bunch of questions about our project. For Scroller we can use the following settings:

-   How would you like to use ESLint? **To check syntax, find problems, and enforce code style**
-   What type of modules does your project use? **JavaScript modules (import/export)**
-   Which framework does your project use? **React**
-   Does your project use TypeScript? **Yes**
-   Where does your code run? **Browser**
-   How would you like to define a style for your project? **Use a popular style guide**
-   Which style guide do you want to follow? **Airbnb**
-   What format do you want your config file to be in? **JavaScript**
-   Would you like to install them now with npm? **Yes**

A `.eslintrc.js` will be created, which contains our configuration for ESLint.

### Adding a lint command

Update our `package.json` file to include a lint script. In the `"scripts"` section add `"lint": "eslint \"src/*\""`, to run linting on all files in the `src/` directory (we need to escape the double quotes because your terminal will try to resolve the glob `*` itself. With quotes around `\"src/*\"` we ignore the terminal's glob resolution and use NodeJS's instead).

```json { actualFilename=./protected/package.json endLine=15 startLine=9 statedFilename=package.json url=https&#x3A;//gitlab.com/fullstackio/books/creating-react-libraries-from-scratch/module_05/lesson_03/protected/package.json#L9 }
  "scripts": {
    "build": "node esbuild.js && tsc",
    "test": "jest",
    "lint": "eslint \"src/*\"",
    "storybook": "start-storybook -p 6006",
    "build-storybook": "build-storybook"
  },
```

Run `yarn lint` to check linting errors.

![A screenshot showing linting errors.](https://d2uusema5elisf.cloudfront.net/courses/creating-react-libraries-from-scratch/module_05/lesson_03/public/lint.png)

## Adding new rules

`eslint init` provided a couple of default rule sets. The first is `plugin:react/recommended`, the recommended linting rules for React, and `airbnb` which is a popular code standard for JavaScript.

The `airbnb` configuration enforces single quotes when creating strings `'`, but we've been using double quotes in Scroller `"`. In the `rules` section, of our `.eslintrc.js` file, add a rule to create an error if we don't use double-quotes. Rules we specify will overwrite the default rules given from the extended configurations.

```js { actualFilename=./protected/.eslintrc.js endLine=18 startLine=16 statedFilename=.eslintrc.js url=https&#x3A;//gitlab.com/fullstackio/books/creating-react-libraries-from-scratch/module_05/lesson_03/protected/.eslintrc.js#L16 }
  rules: {
    quotes: ["error", "double"],
  },
```

We also can turn rules off by adding rules with an `"off"` value. Override a few of airbnb's configurations to match our style.

```js { actualFilename=./protected/.eslintrc.final.js endLine=22 startLine=17 statedFilename=.eslintrc.js url=https&#x3A;//gitlab.com/fullstackio/books/creating-react-libraries-from-scratch/module_05/lesson_03/protected/.eslintrc.final.js#L17 }
  rules: {
    quotes: ["error", "double"],
    "import/prefer-default-export": "off",
    "import/extensions": "off",
    "no-throw-literal": "off",
  },
```

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 Install and Run ESLint When Creating React Libraries