관리-도구

편집 파일: isNaN.js

var isNumber = require('./isNumber'); /** * Checks if `value` is `NaN`. * * **Note:** This method is not the same as [`isNaN`](https://es5.github.io/#x15.1.2.4) * which returns `true` for `undefined` and other non-numeric values. * * @static * @memberOf _ * @category Lang * @param {*} value The value to check. * @returns {boolean} Returns `true` if `value` is `NaN`, else `false`. * @example * * _.isNaN(NaN); * // => true * * _.isNaN(new Number(NaN)); * // => true * * isNaN(undefined); * // => true * * _.isNaN(undefined); * // => false */ function isNaN(value) { // An `NaN` primitive is the only value that is not equal to itself. // Perform the `toStringTag` check first to avoid errors with some host objects in IE. return isNumber(value) && value != +value; } module.exports = isNaN;