In this, you will learn about the various data types available in JavaScript with the help of examples.
There are different types of data that we can use in a JavaScript program. For example:
const x = 5;
Definition
The data type is a basic type of data that can be used in a program. JavaScript provides different data types to hold different types of values. In JavaScript, there is no need to specify the type of variable because it is dynamically used by JavaScript Engine. The different types of data types in JavaScript are shown in the flowchart below
There are two major data types in JavaScript;
- Primitive Data Types
- Non-primitive Data Types/ composite data type
Primitive Data Types Number
- Number- It represents numeric Value
- String- is a sequence of Characters
- Boolean- represent Boolean value either True or False
- Undefined- it represents an undefined value
- Null- represents no value
Number
The number is representing the numeric value, the number type represents integer, float, decimal. You need to use here to specify the datatype. It can hold any type of value
.
<!DOCTYPE html>
<html>
<head>
<title>Java Script</title>
</head>
<body>
<h4>JavaScript</h4>
<p id="p1"></p>
<p id="p2"></p>
<p id="p3"></p>
<script>
var a =100; //integer
var b =10.5; //float
var c =24.00; //decimal
document.getElementById("p1").innerHTML = a;
document.getElementById("p2").innerHTML = b;
document.getElementById("p3").innerHTML = c;
</script>
</body>
</html>
Output:
100 //Integer
10.5 //Float
24 //DecimalString
The string is a sequence of characters, the character must be representing single or double
quotations.
E.g. “Hello World”, „Hello World‟
<!DOCTYPE html>
<html>
<head>
<title>Java Script</title>
</head>
<body>
<h4>JavaScript</h4>
<script>
var fname = "Vijay";
var lastname= "Kumar";
document.write(fname,lastname);
</script>
</body>
</html>
Output
JavaScript
VijayKumar //StringBoolean
Boolean can only have two values, True or False. Boolean is used in conditional testing.
var yes ="true"; var no ="false";
Example
<!DOCTYPE html>
<html>
<head>
<title>Java Script</title>
</head>
<body>
<h4>JavaScript</h4>
<script>
var user = (prompt("Enter the Number"))
if (user < 10)
{
alert("True");
document.write("Welcome to My Article");
}
else
{
alert("False");
document.write("Access denide");
}
</script>
</body>
</html>
Output
Undefined and Null datatype
Variable does not have any value but it will have later on.
var nullvalue = null; alert(nullvalue); // null var nullvalue = null; alert(nullvalue); // null
Non-Primitive Data Type
- Object– Key Value pair
- Array– group of similar values
const y = "Hello";
Here:
- 5 is an integer data.
- “Hello” is a string data.
Summary
| Data Types | Description | Example |
| String | represents textual data | ‘hello’, “hello world!” etc |
| Number | an integer or a floating-point number | 3, 3.234, 3e-2 etc |
| BigInt | an integer with arbitrary precision | 900719925124740999n , 1n etc. |
| Boolean | Any of two values: true or false | true and false |
| undefined | a data type whose variable is not initialized | let a; |
| null | denotes a null value | let a = null; |
| Symbol | data type whose instances are unique and immutable | let value = Symbol(‘hello’); |
| Object | key-value pairs of collection of data | let student = { }; |
Here, all data types except Object are primitive data types, whereas Object is non-primitive.
