/*!
 * Chai - isNaN utility
 * Copyright(c) 2012-2015 Sakthipriyan Vairamani <thechargingvolcano@gmail.com>
 * MIT Licensed
 */

/**
 * ### .isNaN(value)
 *
 * Checks if the given value is NaN or not.
 *
 *     utils.isNaN(NaN); // true
 *
 * @param {unknown} value The value which has to be checked if it is NaN
 * @returns {boolean}
 * @name isNaN
 * @private
 */
function _isNaN(value) {
  // Refer http://www.ecma-international.org/ecma-262/6.0/#sec-isnan-number
  // section's NOTE.
  return value !== value;
}

// If ECMAScript 6's Number.isNaN is present, prefer that.
export const isNaN = Number.isNaN || _isNaN;