JavaScript Data Types

JavaScript Data Types

There are five data types in JavaScript, and they are:

Strings

In my previous posts on JS Basics, I discussed strings. Strings are data, embedded inside quotation marks.

fridge('sweets');

Numbers

In JavaScript, numbers can be assigned to strings.

var myNumber = 12;

There is a difference between assigning a number to a variable, and assigning a stringed number to a variable because they give different results in the console.

var myNumber = 12;
var myString = "12";

Booleans

In JavaScript, a boolean can only have 2 values: true or false. Booleans are mostly used when working with conditionals.

if (myNumber === 12) {
console.log(true)
}

Undefined

undefined in JavaScript means an unassigned variable (variable without a value).

let z
console.log(z); //the result is undefined

Null

null in JavaScript means a variable with no value existing. You can use null to empty an object

person = null; //null is defined as the value

Differences

nullundefined
Defined, but without a valueDon't exist

Summary

There are 5 data types:

  • Strings
  • Numbers
  • Booleans
  • undefined
  • null

At first, they can be difficult to understand, especially undefined and null. But, with constant practice, coding JavaScript with them will be a piece of cake.