Truthy Falsy :

As every data has a type, therefore every each value has an inherit Boolean value. That is either truthy or falsy.

Some falsy values are: 0,false, “”, null, undefined, NaN..

Other than these values every other things are truthy..

Null vs undefined:

In javaScript undefined is a data type but null is an object. Undefined means a variable is declared but never assigned a value. Where null is itself an assigned value. One can add null to any other variable.

Double equal (==):

There is sometime confusions about == and === . So what does it means to write ==?

Comparison is one of the core…

The major features of React are:

  • It uses VirtualDOM instead of RealDOM considering that RealDOM manipulations are expensive.
  • Supports server-side rendering.
  • Follows Unidirectional data flow or data binding.
  • Uses reusable/composable UI components to develop the view.

What is Component:

Components are the core building block of any react component. Combining numbers of components a react app is built. React components are of two categories:

  1. Class Component
  2. Funtion Component

What is State in react app?

State of a component is an object that holds some information that may change over the lifetime of the component. We should always try to make our state as simple as possible and minimize the number of stateful components.

Before react…

Arrow Function:

Arrow function is an alternative way to declare regular function expressions in javascript. Traditional Function need the keyword funtion to declare any function but arrow function is somewhat like declaring a variable and initializing the value with the function arguments.

const namePrint () =>{

console.log(“Name”)

}

Spread Operator(…):

It allows an iterable to expand in places where 0+ arguments are expected. It is mostly used in the variable array where there is more than 1 values are expected. It allows us the privilege to obtain a list of parameters from an array.

let arr1=[1,2,3,4];

let arr2=[6,7,9];

const arr =[…arr1,…arr2]; // returns [1,2,3,4,6,7,9]

Hoisting:

A journey with JavaScript

JavaScript String:

String is a basic data type of JavaScript that holds the character array. A collection of character is called string. For example, lets “JavaScript is a programming language” be a string. Let store the above string in a variable named firstString. Therefore,

const firstString = “JavaScript is a programming language”;

If we want to access a character of the string we can access it in two ways.

const first= firstString[0] // return J

const charfirst = firstString.charAt(1) // return a

Concat method: concat is applied to merge two or more strings together .

const first =” hello”;

const second =…

rafee abdullah

Front End React JS Developer

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