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- var isNumber = require('./isNumber');
- /**
- * Checks if `value` is `NaN`.
- *
- * **Note:** This method is based on
- * [`Number.isNaN`](https://mdn.io/Number/isNaN) and is not the same as
- * global [`isNaN`](https://mdn.io/isNaN) which returns `true` for
- * `undefined` and other non-number values.
- *
- * @static
- * @memberOf _
- * @since 0.1.0
- * @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
- // ActiveX objects in IE.
- return isNumber(value) && value != +value;
- }
- module.exports = isNaN;
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