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  React JS What is the work of ReactJS   it is a framework to build a frontend APP  developed by Facebook. With JavaScript, you can build dynamic applications where the browser performs a substantial part of functions, so they can work without contacting the server. It also allows the data and interface to be updated independently in just a part of an app (without reloading it). The main feature of React.js that distinguishes it from other popular JavaScript frameworks is flexibility. You can take a library and use it to display a simple page or a view, but you can also combine React.js with other tools and use it as a framework that will lay the foundation for a complex application. Understanding the component   These are the building blocks that can be put together to create an application. With React.js it's relatively easy to build custom components, which is a very important feature since building custom components is needed. Components accept arbitrary input named pro

Rest Services

  Rest Services   REST versus SOAP. It's been an issue for a while now. And really, they’re just two answers to the same question: how to access web services.   What is SOAP?   SOAP is a protocol that was planned before REST and came into the image. The fundamental thought behind planning SOAP was to guarantee that projects based on various platforms and programming languages could exchange data in a simple way. SOAP stands for Simple Object Access Protocol. What is REST?  REST is not HTTP but it is using HTTP  REST is not protocol but it using some protocol REST is a guideline to build a performance and scalable system on web REST gives a lighter-weight option. Numerous designers discovered SOAP  uncomfortable  and difficult to utilize. For instance, working with SOAP in JavaScript implies composing a huge load of code to perform basic tasks since you should make the necessary XML structure without fail.   Rather than utilizing XML to make a request, REST (normal

Node.JS

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  Node.JS A runtime environment for executing JavaScript code is open source for developing server-side and networking application Features of Node.JS Asynchronous and Event-Driven The primary organizational concept of Node is to eliminate blocking processes by using event-driven, asynchronous I/O. This design aids developers in shaping data and increasing capacity. Node allows you to create and organize lightweight, self-contained, and share-nothing processes that communicate through callbacks and synchronize with a predetermined event loop. Single-Threaded but Highly Scalable, data-intensive, real-time Node.js is single-threaded but in the background it uses multiple threads to execute asynchronous code This feature because of the non-blocking asynchronous nature of node Has single thread is used to handle multiple requests. It is behind the scene of non-blocking and asynchronous concept   Very Fast Node JS library is very fast in code execution   Where to

NoSQL

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NoSQL It is a family of databases. NoSQL is newer than SQL Most SQL databases are vertically scalable, which means that you can increase the load on a single server by increasing components like RAM, SSD, or CPU. In contrast, NoSQL databases are horizontally scalable, which means that they can handle increased traffic simply by adding more servers to the database The vertically scalable database is adding more power to existing machine A horizontally scalable database is adding more machines to existing network Replication is a crucial part of any database system. It is providing availability and disaster recovery. Mongo DB replication architecture is based on a replica set.it is inattention to the single point of failure     Mongo DB Mongo DB is a document-oriented NoSQL database which means it stores data in JSON-like documents. It is more powerful than the traditional row/column module It is a javaScript base query language It supports aggregation and other mod

Callbacks and Promises

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    Callbacks   In JavaScript, functions are objects. We can pass object as parameter so we can also pass functions as parameters to other functions and call them inside the outer functions. function hello () {       conole.log(“hello world”) ; }   function print ( callback ) {            //other codes are running here          //call hello function, the   all execution finished from this line     callback (); }   Print(hello()); New learn : object can pass as a parameter to a function this mean at function declaration time object was inserted as parameter to function and it can be used inside the outer function. In this example “ createPost ” is a function that is takes “post” as object parameter then at the time of calling argument pass as object into function declaration and it is inserted to the post array by “push” methods   Post one and post two only displayed in the browser post three is not there. In this example after complied the “getPost” fu

How does JavaScript .prototype work?

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How does JavaScript .prototype work? understanding how prototype working for function Prototype object in function: We can create many instances, all instances will have name and age property but address property will not be there inside instances. It will be there inside  prototype object   so that  address we can access from any instance. function have "prototype" property as hidden property that will point to the prototype object and instance also have "__proto__" property as hidden property that also will be point to the same prototype object.            f.prototype.address === fobj.__proto__.address // this will be true, those are pointing same place   understanding how prototype working for class Prototype object in class: The display method is crated inside the class but it is located inside Prototype object  so we can access the display method from both instances. Lisko substitution principle Lisko substitution principle says subclass should be substitut