Node js interview questions with code examples and answers for fresher level

Question 1: How do you print the current working directory in Node.js?

Answer: To print the current working directory in Node.js, use the following code:

console.log(__dirname);

Question 2: How do you import a module in Node.js?

Answer: To import a module in Node.js, use the following code:

const moduleName = require('module-name');

Question 3: How do you export a module in Node.js?

Answer: To export a module in Node.js, use the following code:

module.exports = {
  // module code here
};

Question 4: How do you read command line arguments in Node.js?

Answer: To read command line arguments in Node.js, use the following code:

const args = process.argv.slice(2);

Question 5: How do you create a web server in Node.js?

Answer: To create a web server in Node.js, use the following code:

const http = require('http');

const server = http.createServer((req, res) => {
  // server code here
});

server.listen(3000, () => {
  console.log('Server started on port 3000');
});

Question 6: How do you read and parse JSON data in Node.js?

Answer: To read and parse JSON data in Node.js, use the following code:

const jsonData = require('./data.json');

Question 7: How do you write JSON data to a file in Node.js?

Answer: To write JSON data to a file in Node.js, use the following code:

const fs = require('fs');

const jsonData = {
  // JSON data here
};

fs.writeFile('data.json', JSON.stringify(jsonData), err => {
  if (err) throw err;
  console.log('JSON data written to file');
});

Question 8: How do you read a file line by line in Node.js?

Answer: To read a file line by line in Node.js, use the following code:

const fs = require('fs');
const readline = require('readline');

const rl = readline.createInterface({
  input: fs.createReadStream('file.txt'),
  crlfDelay: Infinity
});

rl.on('line', line => {
  console.log(`Line from file: ${line}`);
});

Question 9: How do you make an HTTP request in Node.js?

Answer: To make an HTTP request in Node.js, use the following code:

const https = require('https');

https.get('https://www.example.com', res => {
  let data = '';

  res.on('data', chunk => {
    data += chunk;
  });

  res.on('end', () => {
    console.log(data);
  });
});

Question 10: How do you use a callback function in Node.js?

Answer: To use a callback function in Node.js, use the following code:

function asyncFunction(callback) {
  // asynchronous code here

  callback();
}

asyncFunction(() => {
  console.log('Callback function called');
});