We can check if a variable is a number in multiple ways.
## isNaN
We can check by calling isNaN
with the variable as the argument. It also detects if a string’s content is a number. For example:
isNaN(1) // false isNaN('1') // false isNaN('abc') // true
Note: isNaN(null)
is true
.
### typeof Operator
We can use the typeof
operator before a variable to check if it’s a number, like so:
typeof 1 == 'number' // true typeof '1' == 'number' // false
How to Check if a Variable is a Number
4 May 2019, Mateusz Zych