asciidisco.com/build/node_modules/is-nan-x/README.md

is-nan-x

ES6-compliant shim for Number.isNaN - the global isNaN returns false positives.

Version: 1.0.1
Author: Xotic750 Xotic750@gmail.com
License: MIT
Copyright: Xotic750

module.exports(value) ⇒ boolean ⏏

This method determines whether the passed value is NaN and its type is Number. It is a more robust version of the original, global isNaN().

Kind: Exported function
Returns: boolean - true if the given value is NaN and its type is Number; otherwise, false.

Param	Type	Description
value	*	The value to be tested for NaN.

Example

var numberIsNaN = require('is-nan-x');

numberIsNaN(NaN);        // true
numberIsNaN(Number.NaN); // true
numberIsNaN(0 / 0);      // true

// e.g. these would have been true with global isNaN()
numberIsNaN('NaN');      // false
numberIsNaN(undefined);  // false
numberIsNaN({});         // false
numberIsNaN('blabla');   // false

// These all return false
numberIsNaN(true);
numberIsNaN(null);
numberIsNaN(37);
numberIsNaN('37');
numberIsNaN('37.37');
numberIsNaN('');
numberIsNaN(' ');