Check if a variable is a number in JavaScript
In this short article, we’ll show you how to check if a variable is a number in JavaScript. Here, you will find the easiest way to check if the value is a number or not. Let’s start with examples.
Ways to check if a variable is a number in JavaScript
1. isNaN() function
The first one is isNaN(), a global variable that stands for is Not a Number. This function returns false if value is a number.
Syntax:
1 | isNaN(variable) |
To check if a variable is a number, we will write condition like below:
1 2 3 4 5 6 7 8 9 10 11 12 | var num = 5; if(!isNaN(num)) { console.log(num + " is a number"); } // Output: 5 is a number var str = "cluemediator"; if(isNaN(str)) { console.log(str + " is not a number"); } // Output: cluemediator is not a number |
2. typeof operator
The typeof operator uses for the check the type of the variable and returns the string. JavaScript has 9 types as below:
- undefined
- null
- boolean
- number
- string
- bigint
- object
- symbol
- function (a special type of object)
Let’s take an example.
1 2 3 4 5 6 7 8 | var num = 567; if(typeof num == "number") { console.log(num + " is a number"); } else { console.log(num + " is not a number"); } // Output: 567 is a number |
That’s it for today.
Thank you for reading. Happy Coding..!!
