NaN, which stands for Not-A-Number. Despite its name,
NaN is a numeric data type used to represent a value that is undefined or not a number in conventional terms. In this blog post, we’ll explore what
- There are built-in functions and operations to test whether a value is
NaN, such as
- Understanding how
NaNto effectively debug and write accurate numerical computations.
Here is a simplified guide to understanding
- Recognize that
NaNis produced by operations that do not result in a clear numeric answer.
- Familiarize yourself with
isNaN(), methods to check for
NaNis not equal to anything, including itself.
- Be cautious of cases where
NaNmight propagate through your calculations without any error being raised.
NaN can arise:
- Math operations that are undefined, such as dividing 0 by 0.
- Conversions of non-numeric strings or symbols to numbers.
- Failures of mathematical functions, like taking the square root of a negative number.
NaN appears in specific situations allows developers to anticipate its occurrence and handle it gracefully in their code.
Testing Against NaN
How do you determine if a value is actually
NaN? Unlike other types of checks, simply using equality checks (like
NaN is ineffective because
- Number.isNaN(): This function determines if the value is
NaNand doesn’t coerce the argument to a number. It’s the recommended method for modern code.
- isNaN(): It also checks for NaN, but it first converts the argument to a number, which sometimes yields unexpected results and is generally less reliable.
Using these functions is crucial to correctly identify
NaN values in your code.
The Unique Behavior of NaN
An intriguing trait of
NaN is that it is not equal to any other value, including itself. This means
NaN === NaN or
NaN == NaN will both return
Another noteworthy behavior is the propagation of
NaN: if any part of a mathematical expression results in
NaN, the whole expression will typically also result in
NaN. This “infectious” nature of
NaN can be useful for indicating an issue at any point in a chain of computations.
Developers should note the function they use to check for
NaN and its browser compatibility, as older browsers may not support
Number.isNaN(). Be sure to check the compatibility tables on resources like MDN for the methods you intend to use.
Call to Action
NaN and its implications. Experiment with the examples provided in this article to see