Wednesday 1 July 2020

Node JS Interview Questions and Answers for 3 Years experience

Question: What is the difference between tilde(~) and caret(^) in package.json?
~ update you to all future patch versions, without incrementing the minor version. ~2.2.3 will use releases from 2.2.3 to 2.3.0.
^ update you to all future minor/patch versions, without incrementing the major version. ^2.3.3 will use releases from 2.3.3 to 3.0.0.

Question: How do I pass command line arguments to a Node.js program?
In Node - How to pass arguent
node process-2.js one two=three four
In Node - How to get argument value

Question: How do I update each dependency in package.json to the latest version?
npm i -g npm-check-updates
ncu -u
npm install

Question: How can I update NodeJS and NPM to the next versions?
npm install -g npm

Question: How to write in files synchronous in Node.js?
const fs = require('fs');
fs.writeFileSync('/fold/test.txt', 'Write in file');

Question: How to read environment variables?
var mode   = process.env.NODE_ENV;
var apiKey = process.env.apiKey; 

Question: How to parse JSON using Node.js?
//Parse JSON Data
var bodyParser = require('body-parser')
app.use(bodyParser.json());       // to support JSON-encoded bodies
app.use(bodyParser.urlencoded({// to support URL-encoded bodies
    extended: true

Question: How  an HTTP POST request made?
var request = require('request');
    { json: { key: 'value' } },
    function (error, response, body) {
        if (!error && response.statusCode == 200) {

Question: How can I get the full object in Node.js's console.log(), rather than Object?
const util = require('util');
console.log(util.inspect(myObject, {showHidden: false, depth: null}));

console.log(JSON.stringify(myObject, null, 4));

Question: How to encode a text using base64?
Buffer.from("Hello World").toString('base64'); //SGVsbG8gV29ybGQ=

Question: How to decoded a text which is encoded with base64?
Buffer.from("SGVsbG8gV29ybGQ=", 'base64').toString('ascii'); //Hello World