Sign in

Null vs Undefined


Simply Undefined means the value you are looking for is not still defined. such as you console.log a value of any object that you had not defined earlier.

see the example:

const premik = {name:”smart dude”, phone:458421};

console.log(premik. gf);(here gf is not mentioned in permik object


Simply the value of null should you explicitly defined or You have defined earlier but somehow it removed

Truthy vs False


In javascript, there are some default value considered as truth such as

‘0’(zero, as a string but only zero is false)

‘ ‘(empty string)

,[](empty array)


false(false keyword himself)




Write programs that do one thing and do it well. Write programs to work together.-Doug Mcllroy

1.Why React?

The main difference between HTML and React is DOM API. react can handle, manage and update DOM more easily using Virtual DOM than HTML this process is called React’s tree reconciliation. React is changing only the content of the element and not the whole DOM tree.

React data flow

In React data goes down the tree of the components. If you want to pass data from parent to child component you need to use props. From JSX point of view props are HTML attributes.

React is not a framework

It is not…

1.Catching,2.Cross-browser testing, 3. Try-Catch,4.Javascript data type


Simply catching is a computer concept that provides the efficiency of disability. Data Cost is a relevant matter in Caching face. Simply the Data Cost is every operation that we do use API.
Catching can manage two way::
A. Client Caching(limit the data Cost by user keeping data locally)
B. Server Catching(limit the Cost incurred by the server and its underlying systems)
The is a new invention Hybrid Caching that marge and manage both types of caching

2. Cross Browser Testing
Cross-browser testing is the practice of making sure that the web sites and web…

Let’s know javascript history details

Simply JavaScript is a programming language Its syntax is based on the Java and C languages.JavaScript was created in 1995 by Brendan Eich while. He was an engineer at Netscape. It was originally going to be called LiveScript.The first edition of the JavaScriptstandard that year and comes through several editions. The 6th major edition of the standard, published in June of 2015.

JavaScript programs manipulate values, and those values all belong to a type. JavaScript’s types are:

Let’s know Types of javascript value details

Let's know about Number details

RIyad Hasan

Front End Web Developer

Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store