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