Q1. How do you install Express.js?
After creating a package.json file, run: npm install express --save. This installs Express and adds it to your dependencies in package.json. The --save flag ensures it's saved in the dependencies list. For development-only tools, you might use --save-dev.
Q2. What is the difference between --save and --save-dev?
--save adds the package to dependencies (required for the app to run in production). --save-dev adds to devDependencies (only needed during development, like testing libraries). For Express, you always use --save because it's required to run your app.
Q3. Where is Express installed in your project?
Express is installed in the node_modules folder. This folder contains all the dependencies. You shouldn't modify this folder manually. The package-lock.json file locks the exact versions installed. The node_modules folder should be ignored in version control (add to .gitignore).
Q4. How do you verify that Express is installed correctly?
Check your package.json file to see if express appears in the dependencies list. Also, you can check the node_modules folder for an express folder. To test, create a simple app.js file that requires express and run it with node app.js.
Q5. Can you install Express globally?
You can install Express globally with npm install -g express, but it's not recommended. Each project should have its own local dependencies to avoid version conflicts. Global installation might be used for command-line tools, but for framework libraries, always install locally.