**Course Title:** Building Mobile Applications with React Native **Section Title:** Introduction to React Native and Setup **Topic:** Setting up the development environment (Node.js, React Native CLI, Expo) ### Overview In this topic, we will guide you through the process of setting up a development environment for building mobile applications with React Native. This includes installing Node.js, React Native CLI, and Expo, which are essential tools for creating and testing React Native applications. ### Installing Node.js Node.js is a JavaScript runtime environment that allows you to run JavaScript on the server-side. It is a prerequisite for installing React Native CLI. To install Node.js, follow these steps: 1. Download the latest version of Node.js from the official Node.js website: <https://nodejs.org/en/download/> 2. Follow the installation instructions for your operating system: * For Windows, run the installer and follow the prompts. * For macOS, use a package manager like Homebrew: `brew install node` 3. Verify that Node.js has been installed by opening a terminal or command prompt and running `node -v` ### Installing React Native CLI React Native CLI is a command-line interface that allows you to create and manage React Native projects. To install React Native CLI, follow these steps: 1. Open a terminal or command prompt and run `npm install -g react-native-cli` 2. Verify that React Native CLI has been installed by running `react-native -v` ### Installing Expo Expo is a framework that allows you to build, deploy, and test React Native applications. To install Expo, follow these steps: 1. Open a terminal or command prompt and run `npm install -g expo-cli` 2. Verify that Expo has been installed by running `expo -v` ### Setting up the Development Environment Once you have installed Node.js, React Native CLI, and Expo, you can set up your development environment. Here are the steps: 1. Create a new React Native project using React Native CLI: `react-native init MyProject` 2. Change into the project directory: `cd MyProject` 3. Install the Expo package: `npm install expo` 4. Initialize Expo: `expo init` ### Initializing Expo When you run `expo init`, Expo will prompt you to choose a template for your project. You can choose from several templates, including a blank template, a tabs template, and a nested navigator template. Here is an example of how to initialize Expo with a blank template: ``` expo init ? Choose a template: blank ? Project name: MyProject ? Do you want to use yarn or npm? (yarn/n) npm Project initialized Assets, fonts, images, APIs, and other static files are stored in the 'public' directory. * index.js - app entry point * App.js - main app component * package.json - app manifest ``` ### Running the Application Once you have initialized Expo, you can run your application using the Expo CLI: `expo start` This will start the Expo development server and open your application in a web browser. ### Summary In this topic, we covered the process of setting up a development environment for building mobile applications with React Native. This included installing Node.js, React Native CLI, and Expo, and initializing Expo. We also ran the application using the Expo CLI. **Key Takeaways:** * Install Node.js as a prerequisite for installing React Native CLI * Install React Native CLI to create and manage React Native projects * Install Expo to build, deploy, and test React Native applications * Initialize Expo to set up your development environment * Run your application using the Expo CLI **Practical Exercise:** 1. Install Node.js, React Native CLI, and Expo on your local machine. 2. Create a new React Native project using React Native CLI. 3. Initialize Expo and choose a template for your project. 4. Run your application using the Expo CLI. **If you have any questions or need help, please leave a comment below.** **What's Next:** In the next topic, we will cover the architecture of React Native applications. We will explore the different components that make up a React Native application, including the app entry point, the main app component, and the package.json file. We will also discuss how to navigate between screens and how to use Expo's APIs to access device features.