JavaScript Struggles — Part 5 | Data Types

2 min readDec 6, 2022

Hey there! 👋🏻
We’re now going to explain the data types of JavaScript, I’m only going to talk this time about the data types themselves, ⚠️ I’m not going to explain the (truthy & false) subject now ⚠️.

This’s just a basic view of the data types of JavaScript.

Data types:-

Undefined
Null
Number
String
NaN

Undefined

Undefined is actually a data type in JavaScript.
Even though that is weird, you'll get used to it.

it’s the default data type if you didn’t assign anything in the variable.

var varName; 

console.log(typeof varName); // outputs: undefined

Null

Null is a data type that has to be assigned.
The best use of it is to find the undefined variables.

Also important to know that null is an object so whenever you want to check the data type of a variable that contains a null it'll return "object".

var nullVariable = null;
var nothingHere;

console.log(nullVariable == nothingHere); // that will output true

But the confusing sometimes, but no worries I covered it already in a previous post

Number

The data type number is so familiar to most developers, it has a number. :)

Simple right?

But sometimes JavaScript has to be JAVASCRIPT and add some weird things around it.
It’s considered bad at math, or to be more specific; it’s actually bad at float-point

Which I’ll cover in an upcoming post, so stay tuned.

String

String is actually so simple.

It’s just like the string of any other language but with some features.

There are 3 ways of using a string in JavaScript:

Single quote 'string'
Double quote "string"
And the backticks

Single quote `'string'`

The single quotes are used just as the normal string.

let stringVar = 'Hello world!';

Double quote `"string"`

This is the normal string itself!!
I think it doesn’t need an explanation.

Backticks

What are even backticks?
It’s the string that uses ` instead of “ or ‘

It’s actually the best practice in my opinion for JavaScript as it provides the formatted string feature with it as you use it, and also enables using multiple lines (it doesn’t apply on the web as you need to use <br />).

let furmattedString = `the answer is ${5 + 5}`;

console.log(furmattedString); // the answer is 10
let multilineString = `Hello there!
I'm Abdelrahman!`;
console.log(multilineString);
/*
Hello there!
I'm Abdelrahman!
*/

NaN

I’ve already explained NaN in the previous post
So let me be the lazy developer I am and not repeat that again 🥱

That’s all for now! I hope you gain anything new from this post. 😄