isNaN

Checks if a value is a an illegal number (Not-a-Number). The function attempts to convert the tested value to a number before checking it. Therefore, a numeric value in string format, for instance, will not be identified as an illegal number.

Syntax

function isNaN(value: any): boolean
 
Parameter Description
value Value you wish to evaluate if it is an illegal number.

Return Value

Examples

In this example:

  • We check if an input variable is an invalid number.
  • If true, we display the following message: Invalid. Please enter a valid number.
  • Otherwise, we display a Success message.
  • For details on how to display messages, see setMessage.
if(isNaN(input)) {
	setMessage('Invalid. Please enter a valid number');
} else {
	setMessage('Success.');
};