It is often required to check the type of a value before performing some operation. Example, it would be better to check if the value of a variable is number before adding another number to it.
This article will explain different ways in which you can check if a value is a number or not.
Method 1: Using typeof operator
Javascript typeof operator is followed by a value or a variable and returns the type of that value or the value contained in a variable.
For numeric data types, it returns ‘number’. By comparing the return value of typeof
with ‘number’, it is possible to check if a value is numeric or not. Example,
Note that with this method you can not tell whether the value is an integer or a decimal.
Method 2: Using Number.isInteger()
Number object provides an isInteger
method which accepts a single argument and returns true
if the type of the argument is an integer, false
it is of any other type(such as a string, decimal, object etc.).
This method can only check for integers and not for decimal values, that is, for decimal values, this method will return false
. Example,
Method 3: Using isNaN function
isNaN
function accepts a single argument and returns true
if the type of argument is a number(integer or decimal), false
if it is of any other type(string, array, object etc.) where NaN stands for Not a Number. Example,
Note that all the methods in this article check if a value is numeric or not, the do not convert a string to number.
Hope you liked this post, why not click the clap icon.