Question 1

What is the significance of the 'npm' command in Node.js?

Accepted Answer

npm (Node Package Manager) is the default package manager for Node.js, used to install, manage, and share dependencies.
- Installs packages listed in package.json.
- Runs scripts for tasks like testing or building.
- Powers the vast npm ecosystem for rapid development.

Question 2

What is the difference between 'let', 'const', and 'var' in Node.js?

Accepted Answer

These are JavaScript variable declarations, used in Node.js.
- 'var' is function-scoped, hoisted, and reassignable.
- 'let' is block-scoped and reassignable.
- 'const' is block-scoped, immutable (but object properties can change).
- Modern Node.js favors let/const.

Question 3

What is the 'http' module’s role in Node.js?

Accepted Answer

The 'http' module enables Node.js to create servers and make HTTP requests.
- Core for building REST APIs or web servers.
- Supports low-level request/response handling.
- Often wrapped by frameworks like Express.
- Lightweight and flexible.

Question 4

What is the role of the module.exports object in Node.js?

Accepted Answer

module.exports is how you expose functionality from a Node.js module to other parts of your app. By default, it’s an empty object, but you can assign functions, objects, or values to it.
- It’s the key to Node’s module system.
- Use exports as a shorthand, but module.exports overrides it.
- Essential for code modularity.

Question 5

What is the role of the 'fs' module in Node.js?

Accepted Answer

The 'fs' (File System) module provides APIs to interact with the file system, like reading, writing, or deleting files.
- Offers both synchronous and asynchronous methods.
- Used for tasks like logging, config management, or file uploads.
- Essential for server-side file operations.

Question 6

What is the purpose of 'npx' in Node.js?

Accepted Answer

npx is a tool bundled with npm to run Node.js packages.
- Executes binaries without global install (e.g., npx create-react-app).
- Runs specific package versions on-demand.
- Simplifies one-off commands.
- Enhances workflow flexibility.

Question 7

What is the role of 'dotenv' in a Node.js project?

Accepted Answer

Dotenv loads environment variables from a .env file into process.env.
- Keeps sensitive data (e.g., API keys) out of code.
- Simplifies environment-specific configs.
- Used in dev; production might use system env vars.
- Enhances security and portability.

Question 8

What is the role of 'nodemon' in Node.js development?

Accepted Answer

Nodemon is a dev tool that auto-restarts a Node.js app when file changes are detected.
- Speeds up development by eliminating manual restarts.
- Configurable via nodemon.json for custom behavior.
- Not used in production; replaced by PM2.

Question 9

What are environment variables and how do you use them in Node.js?

Accepted Answer

Environment variables store configuration settings (e.g., API keys, ports) outside the codebase for security and flexibility.
- Accessed via process.env in Node.js.
- Set in a .env file with the 'dotenv' package or system-wide.
- Crucial for different environments (dev, prod).

Question 10

What is the role of the 'process' object in Node.js?

Accepted Answer

The 'process' object is a global providing info and control over the current Node.js process.
- Access environment variables with process.env.
- Handle events like 'exit' or 'uncaughtException'.
- Get process ID, memory usage, or argv.
- No require() needed.

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