Today I am going to share 10 JavaScript Question which are often asked in Interview. I try to answer it in my way. Feel Free to correct my answer if you find anything wrong or less correct.

  1. What are truthy and falsy value in JavaScript?

Ans. In JavaScript , 0, empty string(‘’), undefined, null, NaN, false are falsy value. On the other hand, true, ‘0’, “ ”, ‘any-string’, [], ‘false’, -1 are truthy value.

2. What is the difference between Null and Undefined?

Ans. In JavaScript almost acted as same. But there is slight difference between them. Null is intentional…

React is by far the most popular JavaScript library for UI (Front End Interface). Today I am trying to explain Core Fundamental of React and Performance boosting of app. In today’s article, I am covering JSX, Virtual DOM, Default Props, Function Component, Class Component and React App Optimization tips.


What is JSX? In one word, JSX is the syntactic sugar for React.createElement function. It makes create element function simpler to create html markup.

React Element without JSX:

const element =
React.createElement(‘div’, {},
React.createElement(‘h1’, {style: {color: ‘red’}},
‘The world isn't simple without JSX.’)

React Element In JSX:

const jsxElement =…

Code or program always doesn’t run the way we want them to run. In our programming life we have to face error too often. Today I am trying to share my error handling and debugging strategy. And I also try to explain try and catch block of JavaScript in a beginner way. Without any further ado, let’s get to the point.

Strategy 1. Rewrite code block:

Most of the times beginner programmer made typing mistake and could not find why their code isn’t working. I face this problem many times, but it is not easy to find where I made that mistake. Later I started…

As a junior developer, we can’t master all the necessary build in function of JavaScript. Here I try to find the most important 10 functions junior developer would need.

Some Important Number method:

  1. parseInt(): The build in parseInt function takes a string and converts it to a number.
parseInt('025', 10) // 25, convert a string to decimal numberparseInt('11', 2) // 3, convert a string to binary numberparseInt('0x10') // 16, browser treats number as hexadecimal if it
starts with 0x
parseInt('0x10', 10) // 0

The 2nd argument is optional. It defines the number types. …

Ishtiak Ahmed

MERN Stack (JavaScript) Web Developer

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