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Lodash _.isNaN


The lodash _.isNaN method is a utility function that checks if a given value is NaN (Not-A-Number) or not. It returns a boolean value denoting whether the provided value is NaN or not. This method supports both number and string data types.

This method uses the global isNaN() function to determine if the value passed is NaN. Since the native isNaN() function coerces non-number values to a number, the lodash implementation adds a number-check before invoking the isNaN() function, ensuring that the value is indeed a number before returning the result.

The _.isNaN method helps in determining the validity of a numeric value. For instance, it can be used to check if the result of a mathematical operation is valid or not. It can also be used to check the validity of the user input, ensuring that only numeric values are accepted.

The example usage of _.isNaN method is illustrated below:

// => true

// => true

// => false

// => false

// => false

// => false

In the above example, the first two arguments are considered as NaN, and the method returns true. The next two values are non-numbers, and the method returns false. The last argument can be converted to a number and is therefore considered a valid number rather than NaN.

In conclusion, _.isNaN is a useful function for checking the validity of numeric values. It checks if a given value is NaN by performing a type check on the input and returns a boolean value denoting whether the provided value is NaN or not.