Forem: Full Stack Tutorials

Deno vs Node | Is Node.js Dead? Future of Deno 2021?

Full Stack Tutorials — Thu, 23 Jul 2020 20:34:43 +0000

Deno is developed to overcome the Node.js Design Issues and provides a new modern development environment using ES6 etc.

Deno vs Node is a very hot topic for the discussion in developer and programmers community since Deno version 1.0 got released.

Node.js and Deno both are very similar. But the question is if we already have Node.js then what is the need for Deno. So Answers of this question is Since JavaScript has changed a lot since 2009 (when node.js was created). Now we have support for Promises, Async/Await, ES modules, Typed Arrays, and TypeScript, etc. Deno has built-in support of these new JavaScript features.

Let's understand both using the following key points.

ES6 Support:
Deno uses ES Modules as the default module system, whereas Node.js uses CommonJS.
TypeScript Support:
Deno supports TypeScript out of the box, which means that we don’t need to manually install and configure tools to write TypeScript code.
Package Manager (NPM):
In Deno, External dependencies are loaded using URLs, similar to browsers. There is also no package manager and a centralized registry like NPM - node_modules.

In short - Deno doesn't use NPM like Node.js. Deno uses modules referenced as URLs.

Deno does not use package.json.

Security: In Node.js application by default has permission to system calls, environment variables, accessing files, sockets, network, etc.

In Deno application you have to provide permissions to the code for system calls, environment variables, accessing files, sockets, network, etc.

Built-in Tools: Deno also provides a set of built-in tools, like a test runner, code formatter and bundler, etc.

Is NodeJS Dead?
Ans:- No

Please share your views in the comment box, Happy Coding!

Node.js Interview Questions Answers - Basic + Advanced

Full Stack Tutorials — Sun, 07 Jun 2020 11:27:20 +0000

Node.js Interview Questions: Node.js Interview Questions and Answers for freshers and Experienced. Basic and Advanced Node.js Questions. Node.js is a JavaScript runtime built on Chrome's V8 JavaScript engine.

Q:- What Is Node.js?

Node.js is an open-source, cross-platform JavaScript runtime environment for executing JavaScript code on server side.

Most Popular JavaScript Engine:

Google Chrome - V8 // Fastest JavaScript Engine
Mozilla FireFox - SpiderMonkey
Microsoft Edge - Chakra

Q:- How to Install Node.js?

It's very easy to Install Node.js on Windows, Linux, etc

Q:- In which Language Node.js is Written?

Node.js is written in‎ - ‎C‎, ‎C++‎, ‎JavaScript and it's original author(s)‎ is ‎Ryan Dahl

Q:- What are the key features of Node.js?

Node.js has many features which makes node.js more powerful.

Asynchronous and Event Driven
It's very fast
Single Threaded & Highly Scalable
Node.js library uses JavaScript
NPM (Node Package Manager)
No Buffering
Community

Let's see all above node.js feature details

Asynchronous and Event Driven:
All APIs of Node.js library are asynchronous, that is, non-blocking I/O.

Node.js can handle multiple concurrent request, it's the power of node.js. After it finish executing request it will run a callback to notify about its completion.
It's very fast:
Node.js uses the Google Chrome's V8 JavaScript Runtime Engine written in C++, which compiles the JavaScript code into machine code, which makes node.js faster.

JavaScript Engine: It is a program that converts JavaScript's code into lower-level or machine code.
Single Threaded & Highly Scalable:
Node.js is a single threaded, which in background (Under the hood Node.js uses many threads through libuv) uses multiple threads to execute asynchronous code.

Node.js applications uses Single Threaded Event Loop Model to handle multiple concurrent requests.

The Event Loop mechanism helps the server to respond in a non-blocking way, resulting in making the server highly scalable as opposed to traditional servers which create limited threads to handle requests.
Node.js library uses JavaScript:
Since, majority of developers are already using JavaScript. so, development in Node.js becomes easier for a developer who already knows JavaScript.
NPM (Node Package Manager):
NPM stands for Node Package Manager, it allows us to install various Packages for Node.js Application.
No Buffering:
Node.js applications never buffer any data. They simply output the data in chunks.
Community:
Node.js has a very good community which always keeps the framework updated with the latest trends in the web development.

Q:- What is NPM? What is the need of NPM in Node.js?

NPM stands for Node Package Manager, it comes with node.js & allows us to install various packages for Node.js Applications.

npm install express --save
npm install lodash --save

Q:- What is "Callback Hell" and how can it be avoided?

Callback hell refers to a coding pattern where there is a lot of nesting of callback functions. The code forms a pyramid-like structure and it becomes difficult to debug.

It is also called - pyramid of doom

Just imagine if you need to make callback after callback:

getDetails(function(a){  
    getMoreDetails(a, function(b){
        getMoreDetails(b, function(c){ 
            getMoreDetails(c, function(d){ 
                getMoreDetails(d, function(e){ 
                    //and so on...
                });
            });
        });
    });
});

Callback Hell can be avoided by using:

Modularizing code
using promise
using async/await

Q:- What is error first callback node.js?

The first argument of the callback is reserved for an error object. If an error occurred, it will be returned by the first err argument.
The second argument of the callback is reserved for any successful response data. If no error occurred, err will be set to null and data will be returned in the second argument.

fs.readFile('myfile.txt', function(err, data) {
// If an error occurred, handle it (throw etc)
if(err) {
    console.log('Error Found:' + err);
    throw err;
}
// Otherwise, log or process the data
console.log(data);
});

Q:- Difference between package.json and package-lock.json?

package.json: The package.json is used for more than dependencies - like defining project properties, description, author & license info etc.

package-lock.json: The package-lock.json is primarily used to lock dependencies to a specific version number.

If package-lock.json exists, it overrules package.json

Q:- What is Modules in Node.js?

This is mostly frequently asked Node.js Interview Questions.

Modules is a set of functionality or javascript libraries encapsulated into a single unit, which can be reused throughout the Node.js application.

Each Node.js modules has it's own context.

Type of Modules in Node.js?

1. Core Modules:

Node.js Core Modules comes with its Installation by default. You can use them as per application requirements

Include and Use Core Modules with Example:

First you need to import core module using require() function.

const http = require('http');

var server = http.createServer(function(req, res){
    console.log("Congrats!, Node.js is running on Port 3000");
});

server.listen(3000);

2. Local Modules:

Local modules are user defined modules which are mainly used for specific projects and locally available in separate files or folders within project folders.

Include and Use Local Module with Example:

First you need to import core module using require() function.

Create a folder common, inside common folder create a new file named utility.js with following code

//create module and export
function log(message) {  
    console.log(message);
}  
module.exports = log;

Now, inside app.js or index.js file import that utility module using require() function.

//load/import module and use
const logger = require('./common/utility');   
var output = logger.log("Congrats!, You have successfully created a local module!");  
console.log(output);

3. 3rd Party Modules:

The 3rd party modules can be downloaded using NPM (Node Package Manager).

Include and Use 3rd Party Module with Example:

//Syntax
npm install -g module_name // Install Globally
npm install --save module_name //Install and save in package.json

//Install express module
npm install --save express  
npm install --save mongoose

//Install multiple modules at once
npm install --save express mongoose

for more detail - please read - Node.js Interview Questions/Answers

Best Node.js Framework [2020]

Full Stack Tutorials — Sat, 25 Jan 2020 13:57:50 +0000

There are a lots of best Node js Framework for Node.js Developer. We have listed top 10 node.js framework which is good to Learn in 2020 to become a JavaScript, Node.js Developer.

What is Framework?

A basic structure of a software system.

A framework is a combination of libraries, helpers, and tools that provide a way to effortlessly build an Applications.

The key aspects of any framework are – its architecture and features

Features of Framework?

Fast Development
Easy Customization
Flexibility
Maintainability
Security
Supports of Libraries

Benefits of using Node js Framework:

Node js framework enables developers to build fast, secure and scalable Applications.

Speed-up custom web application development
Working with databases more efficiently (Using ORM & ODM etc).
Protect websites from targeted security attacks.
Unit Testing Supports.
Easy Maintainance
Built-in Libraries

Express.js

Express.js is the most popular Node.js framework which provides a robust set of features for web and mobile applications.

Installation:

npm install express --save

or 

npm i express

You can use Express application generator to quickly create an application skeleton.

Key Features of Express.js:

Express.js supports MVC Architecture
RESTful APIs Supports
Templating Engines - Jade, EJB, Handlebar etc
Database (RDBMS, NoSQL) - ORM/ODM (Mongoose, Sequalize) supports
Middleware
Routing
Error Handling

Adonisjs

AdonisJs framework runs on almost all major operating systems. It offers you a clean and stable API to build Web apps and micro-services.

Installation:

npm i -g @adonisjs/cli
adonis new yardstick
cd yardstick
adonis serve --dev

MeteorJS

Meteor is a free open source platform for building web and mobile apps in pure JavaScript.

Koa.js

Koa js next generation web framework for node.js.

Hapi.js

Hapi is a rich Node.js framework for building applications and services.

LoopBack

LoopBack is provides a platform for building RESTful APIs and Micro-Services using Node.js

It is an open-source highly-extensible with GraphQL Support Node.js framework for quick RESTful API development.

Sails.js

Sails.js is a Open-source, MVC Node's framework developed at the top the Node.js environment for building custom, enterprise Node.js web applications and APIs.

NestJs

A progressive Node.js framework for building efficient, scalable, and enterprise level server-side applications. it uses TypeScript.

KeystoneJS

KeystoneJS is a framework for developing dynamic websites, apps, CMS and APIs using Node.js, NoSQL (MongoDB | PostgreSQL). It also provides in-built support of CMS/Admin Dashboard.

Feathers

A framework for real-time applications and REST APIs

Key Features of Feathers:

Flexible Plugins Supports
Database Adapters - (In Memory, RDBMS, NoSQL etc)

Install & Create Feathers App:

npm install -g @feathersjs/cli

mkdir my-app

cd my-app

feathers generate app

npm start

What is Model View Controller (MVC)?

MVC stands for "Model-View-Controller." It is a Architectural Pattern.

Model It is for Business Logic.

View It is responsible for Physical Representation - User Interface, Layouts, etc.

Controller It handles & manage all requests of Applications.

How to choose the best Node js framework for your project?

Scalability
Performance
Customization
Libraries Supports
Documentation & Learning Curve
Community Supports
LTS & Versions upgrading
Most Important - Your Knowledge of that Particlar Framework

Core Java Interview Questions

Full Stack Tutorials — Sat, 21 Dec 2019 10:24:33 +0000

Q:- What is Java?

Java is a general-purpose, high level, object-oriented programming language, and java is also platform independent.
Java was originally developed by James Gosling at Sun Microsystems (which has since been acquired by Oracle Corporation) and released in 1995.

Q:- What is the most important features of Java?

1. Simple

Java is very popular general-purpose programming language.

2. Object-Oriented

Java is a pure Object oriented
Every thing in java is object
All programs and data reside inside objects and classes

3. Distributed

Java facilitates it's users to create distributed applications in Java
RMI and EJB are used for creating distributed applications

4. Robust

Java gives importance to memory management by using the technique called Garbage Collection and Exception handling etc.

5. Secure

Java is secure becasue of

Byte code concept
Java is secured because it doesn't use explicit pointers
Exception handling concept
Garbage collection mechanism
Type-safe reference casting in JVM

6. Platform Independent

Java compiler generates a platform-independent code called bytecode.

7. Portable

The Bytecode generated by java can be used on any machine. So it can be portable.

8. Compiled and Interpreted

Generally, computer languages are either compiled or interpreted. but java combines both compilers and interpreters.

9. Performance

The use of a bytecode makes the performance high. the speed is also high with comparing c, c++.

10. Multi-Threading

Multithreading means handling more than one job at a time. Java supports Multithreading.

Q:- How to write very first simple program in Java?

/* This is a very first simple Java program.
   FileName : "FirstProgram.java". 
*/

public class FirstProgram
{
    // Your program begins with a call to main().
    // Prints "Java Interview Questions" to the terminal window.
    
    public static void main(String args[])
    {
        System.out.println("Core Java Interview Questions and Answers for Experienced");
    }
}

//Output: Core Java Interview Questions and Answers for Experienced

Q:- Print "Java Interview Questions" even before main() is executed. How will you achieve that?

You can print the message inside the static block. It will execute when the class gets loaded into the memory and even before the creation of an object.

Hence it will be executed before the main()method. And it will be executed only once.

public class PrintMessage {
    static {
        System.out.println("Core Java Interview Questions");
        System.exit(0);
    } 
}

//Note - 
//1. The System.exit(0) exits the program before the JVM starts to look for main()
//2. This will not work with JDK7 - Because, In JDK7 the code would not execute 
     as it looks for the main method before any other thing.

//Output: Core Java Interview Questions

Q:- What is a Java package and how is it used?

A java package encapsulates a group of similar types of classes, interfaces, and sub-packages.

Use of Packages:

A Package is used to create a separate namespace for groups of classes and interfaces.
A Package are also used to manage and control related classes and interfaces into a single API unit.

Type of Package:

Built-in package: javax, lang, awt, swing, io, util, sql, etc
User-defined package

Q:-Which package is imported by default?

java.lang package

Q:- What is the base class of all classes?

java.lang.Object

Read the complete Article - Core Java Interview Questions and Answers for Experienced

React Interview Questions

Full Stack Tutorials — Sun, 15 Dec 2019 14:12:04 +0000

Q:- What is React.js?

React js is an open-source JavaScript library created by Facebook for building complex and interactive UI in web and mobile applications.

Q:- What are the features of React.js?

Major features of React are listed below:

Virtual DOM: It uses the Virtual DOM instead of the real DOM.
Server-Side Rendering: It uses Server-side rendering (SSR).
Uni-Directional: It follows Uni-directional data flow or data binding.
Components: It uses reusable UI components.

Q:- How to Install React.js using Create React App?

Step-1: First, install react app creator.

For Windows:

npm install -g create-react-app

For Linux and Mac:

sudo npm install -g create-react-app

Step-2: Now, create a your project using react app.

create-react-app myFirstReactProject

Step-3: Now, go to the project folder & start the your app/project.

cd myFirstReactProject
npm start

Q:- What are props in React?

props are immutable passed into react components.

Q:- What is state in React?

State of a component is an object that holds some information that may change over the lifetime of the component.

Changing the state Object:

use this.setState() method to change the state.
Whenever you will change the state, the component will be re-render.

Important Tips:

Never use this.setState() method inside the render.
If you will use this.setState() inside componentWillUnmount(), component will not be re-render.

Q:- What are Components?

Components let you split the UI into independent, reusable pieces, and think about each piece in isolation.

There are mainly two types of Components:

Functional Component (Stateless Component) - Only props, no state
Class Component (Stateful Component) - Both props and state.

Q:- What is Reconciliation?

Reconciliation is the process through which React updates the DOM.

Read the Complete Article React.js Interview Questions & Answers

Architectural Patterns vs Design Patterns

Full Stack Tutorials — Sat, 14 Dec 2019 16:41:35 +0000

Architectural Patterns vs Design Patterns

Generally, the architecture and design both explain the idea but architecture focus on the abstract view of an idea while design focus on the implementation view of the idea.

Design Patterns:

Design patterns - It solves reoccurring problems in the software Design.

Architectural Patterns:

Architectural patterns - It serves as a blueprint for the software systems.

Read Complete Article Architectural Patterns vs Design Patterns

PHP Interview Questions [Core PHP]

Full Stack Tutorials — Wed, 25 Sep 2019 13:43:52 +0000

Q. What is PHP?

PHP is a server-side scripting language designed for web development but also used as a general-purpose programming language.
Originally created by Rasmus Lerdorf in 1994, the PHP reference implementation is now produced by The PHP Group.

PHP originally stood for Personal Home Page, but it now stands for the recursive acronym PHP: Hypertext Preprocessor.

PHP code may be embedded into HTML code, or it can be used in combination with various web template systems, web content management systems, and web frameworks.

Q. Difference between isset() and empty() in PHP?

isset(): checks if a variable has a value including (False, 0, or empty string), but not NULL. Returns TRUE if var exists; FALSE otherwise.

empty(): function checks if the variable has an empty value empty string , 0, NULL ,or False. Returns FALSE if var has a non-empty and non-zero value."

Q. What is the use of explode and implode functions?

Use of explode() and implode() function
explode(): Convert string to Array
implode(): Convert Array to string

Q. What are PSRs? briefly describe it?

PSRs are PHP Standards Recommendations that aim at standardizing common aspects of PHP Development.

An example of a PSR is PSR-4, This PSR describes a specification for autoloading classes from file paths

Q. What is SQL injection?

The SQL injection is a malicious code injection technique. It exploiting SQL vulnerabilities in Web applications

Read more about - PHP Interviews Questions Answers

Jenkins Interview Questions for DevOps Engineer

Full Stack Tutorials — Fri, 23 Aug 2019 21:17:37 +0000

Jenkins is a Continuous Integration (CI) server or tool which is written in Java.

It provides Continuous Integration services for software development, which can be started via command line or web application server.

Jenkins is free software to download and install. Following are some Jenkins interview questions for DevOps engineer which will help you to crack Jenkins Job Interview.

Q:- What is Jenkins?

Jenkins is an open-source Continuous Integration and Continuous Delivery Tool.

Jenkins is a self-contained, open-source automation server which can be used to automate all sorts of tasks related to building, testing, and delivering or deploying software.

Jenkins can be installed through native system packages, Docker, or even run standalone by any machine with a Java Runtime Environment (JRE) installed.

Q:- What is Continuous Integration (CI)?

Continuous Integration (CI) is a development practice where developers integrate code into a shared repository frequently, preferably several times a day. Each integration can then be verified by an automated build and automated tests.

Q:- What are the benefits of Jenkins?

Open-Source: It is an open-source tool and has community support.

Installation: It is very easy to install.

Plugins: It has a large number of plugins to ease your work.

Portable: It is built with Java so, it is portable to all the major platforms.

Version: One can configure Jenkins to pull code from a version control server like GitHub, BitBucket, etc.

MySQL 8.0: New features

Full Stack Tutorials — Mon, 19 Aug 2019 17:04:16 +0000

What Is New MySQL 8 Features?

The following features of MySQL have been added to MySQL 8.0

Character set support

Window Functions

Roles in MySQL 8.0

Invisible indexes support

MySQL Data Dictionary

JSON Enhancements

Node.js Interview Questions

Full Stack Tutorials — Tue, 13 Aug 2019 10:18:11 +0000

Q:- What Is Node.js?

Node.js is an open-source, cross-platform JavaScript runtime environment for executing JavaScript code on server side.

Ryan Dahl came up with a brilliant idea, he thought it would be great to execute JavaScript outside the browser means on the Server, so he took Google's JavaScript V8 Engine and embedded with C++ Program and called it Node.

Most Popular JavaScript Engine:

Google Chrome - V8 // Fastest JavaScript Engine
Mozilla FireFox - SpiderMonkey
Microsoft Edge - Chakra

Q:- What are the key features of Node.js?

Let's look at some of the key features of Node.js

Asynchronous and Event-Driven –

All APIs of Node.js library are asynchronous, that is, non-blocking I/O.

It means that API call doesn't wait for results and doesn't block other calls. After it finishes executing it will run a callback to notify about its completion.

It's very fast –

Node.js uses the Google Chrome's V8 JavaScript Runtime Engine written in C++, which compiles the JavaScript code into machine code making it faster.

It is used for both client-side (Google Chrome) and server-side (Node.js) JavaScript applications.

JavaScript Engine: It is a program that converts JavaScript's code into lower-level or machine code.

Single-Threaded but Highly Scalable –

Node.js is a single-threaded, which in the background (Under the hood Node.js uses many threads through libuv) uses multiple threads to execute asynchronous code.

All Node.js applications use "Single Threaded Event Loop Model" Architecture to handle multiple concurrent clients.

The Event Loop mechanism helps the server to respond in a non-blocking way, resulting in making the server highly scalable as opposed to traditional servers which create limited threads to handle requests.

Node.js library uses JavaScript –

This is another important aspect of Node.js from the developer’s point of view. The majority of developers are already well-versed in JavaScript. Hence, development in Node.js becomes easier for a developer who knows JavaScript.

NPM (Node Package Manager) –

NPM stands for Node Package Manager, it allows us to install various Packages for Node.js Application.

No Buffering –

Node.js applications never buffer any data. They simply output the data in chunks.

Community –

There is an active and vibrant community for the Node.js framework - The active community always keeps the framework updated with the latest trends in web development.

Q:- What is Modules in Node.js?

Modules are a set of functionality or javascript libraries encapsulated into a single unit, which can be reused throughout the Node.js application.