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Getting Started with React

A collection of information about React.js

Created by @itenpn

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Getting Started with React

A collection of information about React.js

Created by @itenpn

You can find this tutorial online at https://hackclub.com/workshops/getting_started_with_react

Getting Started Using React

Table of contents

  1. Assumptions
  2. Installing React
  3. First Steps With React
  4. Making Your Website Appear on Screen
  5. Creating React Components
  6. Using JSX
  7. How to use CSS
  8. Using Props
  9. Using State
  10. General React Tips
  11. Finishing Your Website


  1. You already sort of know how JavaScript works
  2. You already know how to use HTML and CSS
  3. You understand how to access development tools
  4. You have a willingness to problem solve
  5. You have a willingness to start hacking

Installing React

Download the latest version of Node.js

Install react using npm

$ npm install --save-dev react
$ npm install --save-dev react-dom
$ mkdir MyWebsite
$ cd MyWebsite

Create a new project

$ npx create-react-app [Project Name goes here]
$ cd [Project name]
$ npm start

A new localhost window should pop up with the default project

First Steps With React

Open project folder using code editor

  • I recommend VS Code, but any other editor works as well.

Go to the public directory

Edit the index.html file

  • Inside <head> create a <title> for the website
  • Add new fonts if needed

Change the favicon

  • Replace favicon.ico with your own
  • X-Icon can make any image a favicon!
  • This may take a little while to update on localhost

Go to the src directory

  • Delete everything in the src directory, or you can just modify the files if you would like.

Making Your Website Appear on Screen

Create an index.js file in the src directory

  • Import these two modules
import React from 'react'
import ReactDOM from 'react-dom'
  • Import any relevant components from your src folder
  • Proper practice is to import an App.js file that has a render() for all of your components
import { App } from './App.js'

Render your project

ReactDOM.render(<App />, document.getElementById(‘root’));
  • <App /> is a component that displays your website
  • <App /> can be changed to any component that is created in index.js, or is imported

Now you can start creating your project!

Creating React Components

Create a new JS file and its corresponding CSS file


Go to the JS file

  • First lines are always
import React from 'react'
import './ComponentName.css'
  • Import other components from other files if necessary

Create a new class

I’ll use App.js as an example.

export class App extends React.Component {
  //All classes must have a render() method
  render() {
    // You can use control statements to change the return value
    // render() can only return one JSX tag, use <div> to nest tags
    return <div />

Now you have a brand new component!

To import the component to another file

In the new file:

import { ComponentName } from './ComponentName'

To use the component in another file

In the new render() use <ComponentName /> as its JSX

Using JSX

JSX is like HTML you can use inside of React Components

Every render() must return a single JSX tag, so use <div> to nest your HTML.

Some things are different from HTML

  • class is a reserved word in JS, so you must use className instead
  • The style attribute must be passed a JS object, more on that in How to Use CSS

You can insert JS code into JSX tags!

  • Wrap the variable around curly braces {}
  • Works for attributes and inner HTML!

You can insert Components with JSX

  • Just use <ComponentName />

How to use CSS

Import the appropriate CSS file

import 'ComponentName.css'

Go to the CSS file

  • CSS operates just like normal, you can target id, className, and JSX tags

Inline styles are DIFFERENT IN REACT

  • Create a JS object
const style = {}
  • Add a CSS style, but without the hyphens and using camelCase
  • Example:
const style = { fontSize: '24px' }
  • Add a comma at the end of the CSS style if you want to add another
const style = { fontSize: '24px', color: 'blue' }
  • To add an inline style, pass the object to the style attribute
  • Example with style variable:
<h1 style={style}>Hello World</h1>
  • Example with new object:
<h1 style={{ color: 'blue' }}>Hello World</h1>

Using Props

Props stands for properties, they are how we can parameter pass with React

Any JS code can become a prop

  • Functions, variables, etc

Props allow us to communicate to other components

  • Ex: tell a picture w/ caption component to render a certain picture and give it a caption

Props are easy to use

<ComponentName prop1={data} prop2={data2} />
  • Ex:
<Photo picture={JohnDoePicture} caption="John Doe, Manager" />

To gather information from props use: this.props.propName

  • Ex:
<img src={this.props.picture} />

Using State

State tells React when to update a website

  • Anytime state changes, render() is called
  • Use states to change the design of your Component

Accessing a state is easy

  • states can be any data type because they are also a JS object
  • refer to How to Use CSS for more information on objects

To set an initial state, you must add a constructor

constructor(props) {
  this.state = { stateName: data };
  • Inside of the curly brackets above, create a JS object like normal

To change a state, you must use this.setState()

this.setState({ stateName: data })
  • You can pass an object that only changes one state of the component

To change a state within JSX, you must use methods

  • Create a method within the class
methodName(e) {  // you can add more data with methodName(e, data1, data2, etc...
  e.preventDefault(); // prevents the method from running without an event
  this.setState({ // Can accept one or more states, even if you have multiple states
    state1: data1,
    state2: data2
  • Proper practice is to name the method handleEvent, where Event is what activates the method
  • Ex: handleClick
  • To allow this to work, you have to add another line to your constructor
this.methodName = this.methodName.bind(this)

This method can then be attached to events

  • Events trigger when an action occurs
  • onClick, onHover, etc
  • Ex:
<button onClick={this.handleClick}>

To pass additional parameters with the method, you must use a function

e => {
  this.methodName(e, data)
  • Ex:
<button onClick={(e) => { this.handleClick(e, pageNum) }}>

General React Tips

Any changes to a program must be changed using state

  • This includes things such as input boxes or forms

Use a singular App component that displays all of your pages depending on state

  • Use if statements to return different components in your render()

Plan out your project design BEFORE you write code

  • This helps you stay organized and creates a common theme

You can add your own backend code to your React Website

  • Because everyone has a different preference, I will leave this up to you to figure out on your own, but this tutorial starts you off on how to add python to react.

Ask for help!

Finishing Your Website

Create a new repository on GitHub

If you are on Windows, install git

Open the terminal

Go to your project directory

$ cd MyWebsite\ProjectName

Create a new build

$ npm run build

Enter the following commands to add your code to GitHub

# If you haven’t used git before, it will ask you to sign in,
# so do that when it gives you prompts instead of going to the next step.
$ git init
# The period is NOT a typo
$ git add .
$ git commit -m “First Commit”
# Go to GitHub and copy the repository url
$ git remote add origin [Repository URL]
$ git remote -v
$ git push origin master

Now you have your code all on GitHub!

Create an account at Netlify

  • Link your account with the GitHub repository and upload the \build folder
  • Now your website should run on Netlify!

To add a custom domain

  • Go to a domain registrar like GoDaddy
  • Buy a domain name.
  • Insert the custom domain name in Netlify, it will give you several DNS server links
  • On your domain registrar website, go to the DNS server option and link the server links.
  • Wait for a while and your custom domain should now work!


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