NPM will connect to and look in the NPM registry for the package named react, and will download it and install it if it exists.

The following are some useful flags that you can use NPM with:

• --save: This will install and add the package name and version in the dependencies section of your package.json file. These dependencies are modules that your project will use while in production.
• --save-dev: This works in the same way as the --save flag. It will install and add the package name in the devDependencies section of the package.json file. These dependencies are modules that your project will use during development.
• --save-exact: This keeps the original version of the installed package. This means, if you share your project with other people, they will be able to install the exact same version of the package that you use.

While this book will provide you with a step-by-step guide to installing the necessary packages in every recipe, you are encouraged to visit the NPM documentation website at https://docs.npmjs.com/getting-started/using-a-package.json to learn more.