`isNaN()` attempts to convert its argument to a number before checking if it's NaN, while `Number.isNaN()` explicitly checks for NaN without conversion, making the latter more accurate and robust in modern JavaScript environments (ECMAScript 6 and above).
JavaScript's `NaN` value represents an invalid or unreliable result from a mathematical operation, often created by division by zero, invalid numeric conversions, or operations with special values like `Infinity`. It has unique properties that make it challenging to work with. To handle `NaN`, validate user input, use `isNaN()` or `Number.isNaN()`, and be cautious with comparisons.
JavaScript has two functions to detect NaN values: `isNaN()` and `Number.isNaN()`. While similar, they differ in how they handle non-numeric values. `isNaN()` converts values to numbers before checking if they're NaN, while `Number.isNaN()` strictly checks for existing NaN numbers.
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