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1. Truthy and Falsy

Like Data Type, every value in javascript inherently has a boolean value- truthy or falsy. They are called truthy or falsy because they are inherent values until assigned differently.

The values below are always falsy:

  • false
  • 0 (zero)
  • ‘’ , “” (empty string)
  • undefined
  • null
  • NaN

Everything else other than the values mentioned above is truthy.

2. Null and Undefined

React is an open-sourced, front-end, javascript library that builds user interfaces or UI Components. It was created by Jordan Walke, a software engineer at Facebook. This library was first deployed on Facebook’s newsfeed in 2011 and later on Instagram in 2012 and it became open-sourced at JSConf US in May 2013.

According to this Stack Overflow 2020 Developer Survey, which was conducted among 65,000 developers, 35.9% of them selected React in the “Most Popular Technologies” category, making it the 2nd most popular web technology.

Also, in the “Most Loved, Dreaded and Wanted Category”, 68.9% of developers selected it as “Most…

Types are different variations of data that can be stored and manipulated within a program. Every programming language has its own built-in data types and structures that differ from one to another.

According to the latest ECMAScript standard, there are nine data types in Javascript.

The Primitive Types

  • Number
  • String
  • BigInt
  • Symbol
  • Boolean
  • Undefined
  • Null

and, The Structural Types

  • Object
  • Function

Checking the Type

The typeof operator in javascript returns a string that indicates the type of a variable.


Represents a data type that is an integer, float, hexadecimal, octal or exponential value.

In Javascript, a Number is…

Arrays are defined as an ordered list of values in javascript. Where each value inside an array is called an element and each element has a specified index.

The indexing in an array starts from zero. This means if there are six elements in an array the index of the first element will be zero, and the index of the last element will be five.

Take the following code block as an example:

There are…

Arique Ahsan

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