Data Types in JavaScript: An Overview with Examples

JavaScript provides different data types to hold different types of values. There are two types of data types in JavaScript.

1. 1. Primitive data type
2. 2. Non-primitive (reference) data type

Primitive JavaScript data types:

• String [ "Howdy"]
• Number [ 23, 482.038]
• Boolean [ true, false ]
• Null [ null value ]
• Undefined [ value not defined ]
• Objects

Examples:

• Numbers are only double precision 64-bit values. There are no integers in JS. For example – 42 or 42.39794
• Strings are to store characters.
• Booleans are true and false.
• Undefined is unique to JavaScript. It is a data type assigned to variables that are declared as variables but not assigned any values.
• Null is a type to denote null value.

var length = 16;                               // Number
var lastName = "Ansari";                      // String
var x = {firstName:"Rambo", lastName:"Azmi"};    // Object

JavaScript is a dynamic type language, means you don't need to specify type of the variable because it is dynamically used by JavaScript engine. You need to use var here to specify the data type. It can hold any type of values such as numbers, strings etc. For example:

var a=80;//holding number  
var b="Rambo";//holding string  

Overview

JavaScript non-primitive data types

The non-primitive data types are as follows:

We will have great discussion on each data type later.

Primitive data types does not have any methods.

JavaScript provides wrapper objects for the primitive datatypes with methods implemented.

For the primitive datatypes : null, undefined : there are no Wrapper Objects.