Artwork: https://code-art.pictures/
Code on artwork: React JS
Why bother if there is create-react-app?
Good question! In fact, if you are happy with create-react-app
— just use it 🙂 But if you want to figure out how everything works together, let's combine all parts ourselves!
Dear reader and my fellow dev,
I try my best keeping the post up to date. However, if you find anything wrong or outdated, please write a comment, thank you!
Structure of the project we are going to create
/hello-react
/dist
index.html
main.css
main.js
main.js.LICENSE.txt
/src
index.css
index.tsx
index.html
package.json
tsconfig.json
webpack.config.js
1. Install Node.js and npm
Node.js installation steps depend on your system — just proceed to a download page and follow instructions.
npm doesn't need any installation because it comes with Node. If you wish to check that everything is properly installed on your system, follow these instructions.
Sidenotes: node and npm are not the only options. There's Deno which is alternative to node, and Yarn which is alternative to npm. If uncertain, I'd recommend staying with node + npm for the moment.
2. Create the project
Create the project root dir, hello-react
, and run npm init
wizard from inside it:
mkdir hello-react
cd hello-react
npm init
The wizard creates an empty project asking you questions one by one. To automatically accept all default answers, append -y
param to npm init
command. Once wizard finishes, it creates the following file:
package.json (created by npm init
)
{
"name": "hello-react",
"version": "1.0.0",
"description": "",
"main": "index.js",
"scripts": {
"test": "echo \"Error: no test specified\" && exit 1"
},
"author": "",
"license": "ISC"
}
Not much, but... that's already a valid Node.js project! 🎊
3. Install TypeScript
Staying in the project root dir run this:
npm i --save-dev typescript
4. Create tsconfig.json
That's TypeScript configuration for the project. Create it in the project root dir and insert the following content:
tsconfig.json
{
"compilerOptions": {
"esModuleInterop": true,
"jsx": "react",
"module": "esnext",
"moduleResolution": "node",
"lib": [
"dom",
"esnext"
],
"strict": true,
"sourceMap": true,
"target": "esnext",
},
"exclude": [
"node_modules"
]
}
What these mean? Let's see!
-
compilerOptions
-
esModuleInterop
— the flag fixes default and namespace imports from CommonJS to TS. That's just needed 🙂 -
jsx
— tells TS how to treat JSX files -
module
— the option tells TS how to transpile ES6 imports and exports;esnext
leaves them unchanged. I recommend setting alwaysesnext
to leave this job to webpack. -
moduleResolution
— historically TS used to resolve modules in other way than Node.js, so this must be set tonode
-
lib
— this option tells TS which libraries will exist in your target environment, so TS implicitly imports their types. TS won't be able to check if these libs really exist in runtime, so that's your promise. More on this later. -
strict
— enables all TS type checks -
sourceMap
— enables TS emitting source maps. We will configure webpack to ignore source maps in production builds. -
target
— configures target ES version which depends on your users; more on this later.
-
-
exclude
— this option excludes libs from typechecking and transpiling; however your code is still checked against typedefs provided by libs.
Full tsconfig.json
reference is here.
5. Install webpack, plugins and loaders
Staying in the project root dir, execute the following command. It's long, so make sure you scrolled enough and copied the whole line!
npm i --save-dev webpack webpack-cli webpack-dev-server css-loader html-webpack-plugin mini-css-extract-plugin ts-loader
6. Create webpack.config.js
Create webpack.config.js
in the project root dir, and insert the following content:
webpack.config.js
const prod = process.env.NODE_ENV === 'production';
const HtmlWebpackPlugin = require('html-webpack-plugin');
const MiniCssExtractPlugin = require('mini-css-extract-plugin');
module.exports = {
mode: prod ? 'production' : 'development',
entry: './src/index.tsx',
output: {
path: __dirname + '/dist/',
},
module: {
rules: [
{
test: /\.(ts|tsx)$/,
exclude: /node_modules/,
resolve: {
extensions: ['.ts', '.tsx', '.js', '.json'],
},
use: 'ts-loader',
},
{
test: /\.css$/,
use: [MiniCssExtractPlugin.loader, 'css-loader'],
},
]
},
devtool: prod ? undefined : 'source-map',
plugins: [
new HtmlWebpackPlugin({
template: 'index.html',
}),
new MiniCssExtractPlugin(),
],
};
A lot of things are going on here! webpack configuration is arguably the most complex thing in the whole setup. Let's see its parts:
- Setting a
NODE_ENV
var is the typical way of setting a dev/prod mode. See later how to set it in your script. -
HtmlWebpackPlugin
generatesindex.html
from a template which we are going to create shortly -
MiniCssExtractPlugin
extracts styles to a separate file which otherwise remain inindex.html
-
mode
tells webpack if your build is for development or production. In production mode webpack minifies the bundle. -
entry
is a module to execute first after your app is loaded on a client. That's a bootstrap that will launch your application. -
output
sets the target dir to put compiled files to -
module.rules
describes how to load (import) different files to a bundle-
test: /\.(ts|tsx)$/
item loads TS files withts-loader
-
test: /\.css$/
item loads CSS files
-
-
devtool
sets the config for source maps -
plugins
contains all plugins with their settings
Phew! The most complex part is behind.
7. Add scripts to package.json
Add start
and build
scripts to your package.json
:
package.json (Linux, OS X)
{
...
"scripts": {
"start": "webpack serve --port 3000",
"build": "NODE_ENV=production webpack"
}
...
}
package.json (Windows PowerShell)
The build
command has to be different:
{
...
"scripts": {
"start": "webpack serve --port 3000",
"build": "set NODE_ENV=production && webpack"
}
...
}
-
start
launches a dev server on port 3000. Dev server automatically watches your files and rebuilds the app when needed. -
build
builds your app for production.NODE_ENV=production
setsNODE_ENV
which is checked in the first line ofwebpack.conf.js
.
8. Create index.html template
HtmlWebpackPlugin
can generate HTML even without a template. However, you are likely going to need one, so let's create it in the project root dir. It's the file we referenced from webpack.config.js
plugins section.
index.html
<!DOCTYPE html>
<html>
<head lang="en">
<title>Hello React</title>
</html>
<body>
<div id="app-root">App is loading...</div>
</body>
9. Install React
Staying in the project root dir, run the following:
npm i react react-dom
And then:
npm i --save-dev @types/react @types/react-dom
10. Create src/index.tsx
That's the entry point of your application; we've referenced it from webpack.config.js
. You may also fix main
to point to the same file in package.json
, though it's not required.
src/index.tsx
import React from 'react'
import { createRoot } from 'react-dom/client'
const container = document.getElementById('app-root')!
const root = createRoot(container)
root.render(<h1>Hello React!</h1>)
Note: createRoot()
API is new to React 18. If you need an older version, you may read this blogpost, and use the following code:
src/index.tsx for React 17
import React from 'react'
import ReactDOM from 'react-dom'
ReactDOM.render(
<h1>Hello React!</h1>,
document.getElementById('app-root'),
)
11. Create src/index.css and import it to src/index.tsx
To make sure our CSS plugin works, let's apply some styles.
src/index.css
body {
color: blue;
}
src/index.tsx
import './index.css'
// The rest app remains the same
// ...
12. Run dev server
It was very long path! But we are close to the end. Let's run the dev server:
npm start
Now open http://localhost:3000/ in your browser — you should see the colored greeting:
Hello React!
Now try to modify src/index.tsx
, for example, change a message — app must reload and show an updated text; try also change styles — they must be also picked up without server restart.
13. Build your app for production
Staying in project root dir, run this:
npm run build
You should observe appeared dist
folder with bundle files generated. Let's try serving them as in real production:
npx serve dist
serve is a simple Node.js program that serves static files. Once launched, it outputs the URL it serves your app from, usually it's http://localhost:3000/. Open it — you should see the greeting.
14. Targeting older environments
That's a bit advanced part, so you may postpone it until you are comfortable with the basic setup.
14.1. Target ES version
Target ES is set in tsconfig.json
: compilerOptions.target
, and it depends on who you write your app for. So who is your user?
- You and your team — my bet you don't use anything obsolete 🙂 So it's safe to leave
esnext
- Average Internet user — my guess would be
es<currentYear-3>
, i.e. on a year of this writing (2021) it'd bees2018
. Why notesnext
? There may be interesting surprises even in seemingly recent devices, for example, Xiaomi MIUI Browser 12.10.5-go released on 2021 May does not support nullish coalesce operator, here's a pen for Xiaomi users. What's your result? - IE users — then target must be
es5
. Note: some ES6+ features get bloated when transpiled to ES5.
14.2. Select target libs
Libs are set in tsconfig.json
: compilerOptions.lib
, and the option also depends on your guess about your user.
Typical libs:
-
dom
— this includes all APIs provided by the browser -
es...
, for examplees2018
— this includes JavaScripts builtins coming with corresponding ES specification.
Important: unlike Babel, these options don't add any polyfills, so if you target older environments you have to add them like described next.
14.3. Add polyfills
This depends on APIs your app needs.
- React requires: Map, Set and requestAnimationFrame which do not exist in old browsers
- If your client code uses some relatively new API like flatMap or fetch while targeting older browsers, consider polyfilling them as well.
Here are some popular polyfills:
- core-js for missing Set, Map, Array.flatMap etc
- raf for missing requestAnimationFrame
-
whatwg-fetch for missing
fetch
. Note: it doesn't includePromise
polyfill. It's included in above-mentionedcore-js
.
Given we decided to use all of them, the setup is the following:
npm i core-js raf whatwg-fetch
index.tsx
import 'core-js/features/array/flat-map'
import 'core-js/features/map'
import 'core-js/features/promise'
import 'core-js/features/set'
import 'raf/polyfill'
import 'whatwg-fetch'
// The rest app remains the same
// ...
14.4. Tweaking webpack
runtime
It may be surprising, but even if you transpile to ES5, webpack
may emit the code with ES6+ constructs. So if you target something ancient like IE, you may need to turn them off. See this.
Is it fair adding so much polyfills?
No, it's not given most users have quite a good browser and just wasting their runtime and bandwidth. So the best option would be making 2 bundles: for old and new environments, and load only one of them. The topic falls outside of this tutorial.
You're done!
I know that wasn't that easy 😅 But I'm sure these things are no more a puzzle for you. Thanks for staying with me for this journey!
Top comments (15)
Great resource!
Just wanted to make a small addition regarding the build script:
On windows, this doesn't work. Replacing it with:
will make it work on windows.
Cheers :)
Thanks, added a different fragment for Windows
@alekseiberezkin awesome article, thankyou!
Great job. congrats
Excellent resource! Thanks for keeping it up to date!
great.
12.1 - compilerOptions.ta*R*get 😉
Thx, fixed
@alekseiberezkin is there any chance of changing webpack for esbuild? thanks for the article
Thx for the suggestion. You are right, esbuild is not more an “emerging” tool but a comprehensive alternative. Unfortunately I can't give any estimate when I'm able to look at it closely because right now I'm not working in frontend fulltime. However if I decide writing about something here, that'd be among the first topics to consider.
Thanks @alekseiberezkin for the tutorial, it was really helpful but I think you missed to add
@types/react
and@types/react-dom
Thank you so much, updated the post
@alekseiberezkin Thank you for the article. Will definitely try this. Meanwhile, I have a similar article, that you might like - React from scratch
Thanks for your link. Will keep it in mind if I need Babel.
Please add
meta name="viewport" content="width=device-width, initial-scale=1"
to index.html
I spent a lot of time trying to understand why 'min-width' doesn’t work for me.