An array data is a data structure consisting of a collection of elements where each elements are identified by array index or key. Simply, an array is a special variable, which can hold more than one value at a time. An array is stored such that the position of each element can be computed from its index tuple by a mathematical formula.

Some Array methods and description:


Used to merge two or more arrays.

const array1 = ['a', 'b', 'c'];
const array2 = ['1', '2', '3'];
const array3 = array1.concat(array2);
// output: Array ["a", "b", "c", "1", "2", "3"]


Returns result whether…


React hook is the addition in React 16.8 which lets React features without writing a class. Lets have a look:

import React, { useState } from 'react';
function Example() {
// Declare a new state variable, which we'll call "count"
const [click, setClick] = useState(0);
return (
<p>You clicked {click} times</p>
<button onClick={() => setClick(click + 1)}>
Click me

Here, useState is a Hook. To add some local state to it, we call it inside a function component. React will preserve this state between re-renders.


React is a JavaScript library. React is not a framework. There are a lots of JavaScript framework like: Angular JS, Vue JS etc. But react is not a framework. It is a front end JavaScript library for building user interfaces or UI components. In react, we import React to use React, import React DOM to use it, import almost everything we use featured in React. So, React is a JavaScript library where we need to import to use it.

React is thin and it’s extremely easy to mix it with other 3rd party libraries. …

ES6 refers to ECMAScript 2015, the sixth edition of the ECMAScript Language Specification standard. After ES6, working with some tools like Block Bindings and Function has become much easier.

Block Binding

Variable declarations has been one tricky part of in JavaScript from the beginning. In other programming languages like: C languages, variables (or bindings) are created at the spot where the declaration occurs. But in JavaScript, your variables are actually created depending on your declaration. Now, ECMAScript 6 offers options to make these much easier.

Declarations and Hoisting

Block declarations and hosting are those that declare variables that are accessible…

A number is a mathematical object. It is used to count, measure, and label. Like every programming language, JavaScript also provides support for manipulating different types of numbers such as simple whole integers and floating point number.

isNaN() :

Determines whether the value is an illegal number / not a number

isNaN(123) //false
isNaN(-4.53) //false
isNaN(undefined) //true
isNaN('NaN') //true


Returns a floating point number. If unable to parse, returns NaN.

var a = parseFloat("20")
var b = parseFloat("20.33")
// output: 20
// output: 20.33


Parses a string and returns an integer

var a = parseInt("20")

Strings are very useful for holding data that can be represented in text form. Like other programming languages, strings are used to represent and manipulate a sequence of characters in JavaScript.

charAt() :-

Returns the character at the specified index (position)

return 'cat'.charAt(2) // returns "t"return 'dog'.charAt(0) // returns "d"


Joins two or more strings, and returns a new joined

const str1 = "Ariful";
const str2 = "Sagor";
console.log(str1.concat(" ", str2));
// output: "Ariful Sagor"
console.log(str2.concat(", ", str1));
// output: "Sagor, Ariful"


Checks whether a string contains the specified string/character

const sentence = 'The fox cut off…

JavaScript is one of the most popular programming languages. It is often abbreviated as JS. It is a high level, lightweight, interpreted, just-in-time compiled programming language with first-class functions. JavaScript is used for solving many programming problems and building cool programs. But mostly it is used in web Development. It is mainly used on a static lifeless website to give life and interact with users and make the whole website dynamic.

JavaScript was created in 1995 by Brendan Eich. At first the language was named ECMAScript initially. Later it was named LiveScript. Finally JavaScript due to huge popularity on language…

Ariful Islam

Mechatronics Engineer | Front-End Web Developer

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