mathjs/lib/function/utils/isNaN.js

Math.js is an extensive math library for JavaScript and Node.js. It features a flexible expression parser with support for symbolic computation, comes with a large set of built-in functions and constants, and offers an integrated solution to work with dif

'use strict';

var deepMap = require('../../utils/collection/deepMap');

function factory(type, config, load, typed) {
  /**
   * Test whether a value is NaN (not a number).
   * The function supports types `number`, `BigNumber`, `Fraction`, `Unit` and `Complex`.
   *
   * The function is evaluated element-wise in case of Array or Matrix input.
   *
   * Syntax:
   *
   *     math.isNaN(x)
   *
   * Examples:
   *
   *    math.isNaN(3)                     // returns false
   *    math.isNaN(NaN)                   // returns true
   *    math.isNaN(0)                     // returns false
   *    math.isNaN(math.bignumber(NaN))   // returns true
   *    math.isNaN(math.bignumber(0))     // returns false
   *    math.isNaN(math.fraction(-2, 5))  // returns false
   *    math.isNaN('-2')                  // returns false
   *    math.isNaN([2, 0, -3, NaN]')      // returns [false, false, false, true]
   *
   * See also:
   *
   *    isNumeric, isNegative, isPositive, isZero, isInteger
   *
   * @param {number | BigNumber | Fraction | Unit | Array | Matrix} x  Value to be tested
   * @return {boolean}  Returns true when `x` is NaN.
   *                    Throws an error in case of an unknown data type.
   */
  var isNaN = typed('isNaN', {
    'number': function number(x) {
      return Number.isNaN(x);
    },
    'BigNumber': function BigNumber(x) {
      return x.isNaN();
    },
    'Fraction': function Fraction(x) {
      return false;
    },
    'Complex': function Complex(x) {
      return x.isNaN();
    },
    'Unit': function Unit(x) {
      return Number.isNaN(x.value);
    },
    'Array | Matrix': function ArrayMatrix(x) {
      return deepMap(x, Number.isNaN);
    }
  });
  return isNaN;
}

exports.name = 'isNaN';
exports.factory = factory;