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node-js / Reading Files
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Q1. How do you read a file asynchronously in Node.js?
Use fs.readFile() with a callback. Example: 
const fs = require('fs'); fs.readFile('example.txt', 'utf8', (err, data) => { if (err) { console.error(err); return; } console.log(data); });
The 'utf8' encoding returns the file content as a string. Without encoding, it returns a buffer. Always handle errors properly.
Q2. How do you read a file synchronously?
Use fs.readFileSync(). Example: 
try { const data = fs.readFileSync('example.txt', 'utf8'); console.log(data); } catch (err) { console.error(err); }
. Synchronous methods block the event loop, so they're not recommended for production servers handling many requests. They're okay for initialization scripts or CLI tools.
Q3. How do you read a file using promises?
Use fs.promises.readFile(). Example: 
const fs = require('fs').promises; async function readFile() { try { const data = await fs.readFile('example.txt', 'utf8'); console.log(data); } catch (err) { console.error(err); } }
. This combines the benefits of async operations with cleaner syntax using async/await.
Q4. How do you read large files efficiently?
For large files, use streams: fs.createReadStream(). This reads the file in chunks without loading the entire file into memory. Example: 
const readStream = fs.createReadStream('largefile.txt', 'utf8'); readStream.on('data', (chunk) => { processChunk(chunk); }); readStream.on('end', () => { console.log('Done'); });
Q5. How do you handle different encodings when reading files?
You can specify encoding as the second argument: 'utf8', 'ascii', 'base64', 'hex', etc. If you need to handle binary data, omit encoding to get a buffer. You can also specify encoding in the options object: 
fs.readFile('file.txt', { encoding: 'utf8', flag: 'r' }, callback);