Quickly initialize a React app with create-react-app

create-react-app is an npm module that sets up a skeleton React application from scratch. It will quickly and seamlessly create a scaffolding with all the directories, files, and libraries required to jumpstart an application.
You can find the project homepage here.

create-react-app sets up the environment for developing and running a React application. It creates a project directory and initializes a package.json file with all the required dependencies, including Babel, and tools like react-script that do the transpiling automatically.

This is the command we run to create a React application. Replace app-directory with the name of the directory that contains the application.

npx create-react-app app-directory

Running this command creates the named directory and a package.json file inside of it.
It then downloads all the necessary npm modules and adds a start script that we can use to start the React application.

We can also run create-react-app from inside an existing directory, but we should make sure the directory is empty or we wouldn’t be able to run the command:

// run the command from inside a directory

npx create-react-app .

We can run the start script either with npm or yarn, from inside the project directory.

npm start

// or 

yarn start

The application will be started and automatically served on port 3000.
We can open the base application in our browser by navigating to http://localhost:3000

create-react-app builds a directory structure with a public directory and a src directory.
Within the public directory there's an index.html file that is used as the entry point of our application.

index.html contains a div element with an id of root that functions as the mount point for the React application.
The whole React application will be contained within this root element, and as
we will see, it will be built up of many components.

Tomorrow we are going to see how to build React functional components.