React 00 - Beginner : React + Typescript from scratch
Tags: react, typescript, webpack, html
Published: 2020-10-26 19:44:44

---
series: React overview for beginner
---
This post aims to show how to start a simple project in React and Typescript, without using create-react-app or any other scaffolding tool.

We will see how to install the minimum number of dependencies to start and try to explain each command or dependency addition.

You need to have [node.js](https://nodejs.org) installed on your dev environment.

### Setup environment
To get started, create a directory for your project.
I would use Vs code in this post.

Open the directory from Vs code, then open a command line. You should have something like that

![Alt Text](https://dev-to-uploads.s3.amazonaws.com/i/4w57i7diigqhi7fdaknm.PNG)

Now you need to initialize the package.json to save the dependencies and scripts.

I usually use yarn but you can use npm too

```bash
# With Yarn
yarn init -y

# With npm
npm init -y
```

This will add a `package.json` file at the root.
We need to add typescript as a dev dependency to compile our code.

```bash
# With Yarn
yarn add -D typescript

# With npm
npm i -D typescript
```

We also need to install webpack to pack the project and make it suitable for the browser

```bash
# With Yarn
yarn add -D webpack webpack-cli

# With npm
npm i -D webpack webpack-cli
```
And to run the project locally we need a little standalone http server

```bash
# With Yarn
yarn add -D http-server

# With npm
npm i -D http-server
```

### A little bit of configuration
In order to make the compiler works properly we need to add a typescript configuration file:

```bash
# With Yarn
yarn tsc --init

# With npm
npx tsc --init
```

this will add a default `tsconfig.json` file at the root.

Edit the file, and configure it as follow : 

```json
{
  "compilerOptions": {
    "target"                           : "es6"      ,
    "module"                           : "commonjs" ,
    "jsx"                              : "react"    ,
    "outDir"                           : "./out"    ,
    "rootDir"                          : "./src"    ,
    /* Default flags */
    "strict"                           : true       ,
    "esModuleInterop"                  : true       ,
    "skipLibCheck"                     : true       ,
    "forceConsistentCasingInFileNames" : true
  }
}
```

This configuration will assume the following :

* The target output will be ES6 compliant
* The JSX templates will be compiled by the typescript compiler so no need to use babel
* The output will be placed in the `out` folder
* The source code will be placed in the `src` folder

At this point, you can write and compile files, but we need now to configure Webpack to pack the output.

Create a file named `webpack.config.js` at the root, and put the following inside

```js
const path = require('path');

module.exports = {
  entry  : './out/App.js',
  output : {
    path     : path.resolve(__dirname, 'www/js'),
    filename : 'app.js'
  },
  externals : {
    "react"     : 'React',
    "react-dom" : 'ReactDOM'
  },
};
```

This configuration will assume the following :

* The entrypoint is located here : `./out/App.js`
* The output will be placed here : `./www/js.app.js`
* react and react-dom packages will not be packed as we will add them from a CDN, to speed up the packing time.

### You first `TSX` file

When coding React with Typescript, you will not use JSX files with javascript but the counterpart TSX files. Exactly the same syntax but with typescript instead of javascript inside.

So Let's create our first file in the src folder, named App.tsx
```tsx
import * as React from "react"     ;
import { render } from "react-dom" ;

render(<> Hello kitty </>, document.querySelector("#app"));
```

Very simple sample of code, but it does the job :-)

Now you need a last addition, the `index.html` file.

Create an `index.html` file located here : `www/index.html`
```html
<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <script crossorigin src="https://unpkg.com/react@16/umd/react.development.js"></script>
  <script crossorigin src="https://unpkg.com/react-dom@16/umd/react-dom.development.js"></script>
  <title>Document</title>
</head>
<body>
  <div id="app"></div>
  <script src="js/app.js"></script>
</body>
</html>
```

At the end of the file, we added a div with the `id` `app`, and the script reference to the packed application.

### It's building time
To build and pack, you just need 2 commands

```bash
# With Yarn
yarn tsc

# With npm
npx tsc
```

This will compile the project and output the result in the `out` folder

Then you need to pack it

```bash
# With Yarn
yarn webpack

# With npm
npx webpack
```

*If you want to use the watcher to not re run the commands each time, you can add the `-w` flag to run each command in watch mode*

```bash
# With Yarn
yarn tsc -w

# With npm
yarn webpack -w
```

If everything goes well you have this : 

![Alt Text](https://dev-to-uploads.s3.amazonaws.com/i/aarz6nh520mlbrscyjfn.PNG)

### Browsing the result 

To finish you need to serve the project locally, so you can start a webserver to serve it

```bash
# With Yarn
yarn hs ./www

# With npm
npx hs ./www
```

Now open your browser and navigate to http://localhost:8080 to see this (I hope)

![Alt Text](https://dev-to-uploads.s3.amazonaws.com/i/4w8zwh3tpcll5trxtdku.PNG)

Enjoy !