| Leo Repp | 58b9f11 | 2021-11-22 11:57:47 +0100 | [diff] [blame^] | 1 | var isNumber = require('./isNumber'); |
| 2 | |
| 3 | /** |
| 4 | * Checks if `value` is `NaN`. |
| 5 | * |
| 6 | * **Note:** This method is based on |
| 7 | * [`Number.isNaN`](https://mdn.io/Number/isNaN) and is not the same as |
| 8 | * global [`isNaN`](https://mdn.io/isNaN) which returns `true` for |
| 9 | * `undefined` and other non-number values. |
| 10 | * |
| 11 | * @static |
| 12 | * @memberOf _ |
| 13 | * @since 0.1.0 |
| 14 | * @category Lang |
| 15 | * @param {*} value The value to check. |
| 16 | * @returns {boolean} Returns `true` if `value` is `NaN`, else `false`. |
| 17 | * @example |
| 18 | * |
| 19 | * _.isNaN(NaN); |
| 20 | * // => true |
| 21 | * |
| 22 | * _.isNaN(new Number(NaN)); |
| 23 | * // => true |
| 24 | * |
| 25 | * isNaN(undefined); |
| 26 | * // => true |
| 27 | * |
| 28 | * _.isNaN(undefined); |
| 29 | * // => false |
| 30 | */ |
| 31 | function isNaN(value) { |
| 32 | // An `NaN` primitive is the only value that is not equal to itself. |
| 33 | // Perform the `toStringTag` check first to avoid errors with some |
| 34 | // ActiveX objects in IE. |
| 35 | return isNumber(value) && value != +value; |
| 36 | } |
| 37 | |
| 38 | module.exports = isNaN; |