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Javascript Check For Nan: Javascript Explained

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Javascript is a high-level programming language which is becoming increasingly popular as a web development language. Working with complex structures and numbers, it is important to consider a few things, one of which is Nan, or “Not-a-Number”. Understanding what Nan is, how to check for it in Javascript, and benefits in doing so are all essential concepts for anyone looking to work with numerical values in Javascript.

What is Nan in Javascript?

In Javascript, Nan (Not-a-Number) is a special value that results from an operation which produces a result that isn’t a number or other primitive type. For example, if a user attempts to do arithmetic with a value that is not a number, the result will be Nan. Additionally, if a user attempts to convert something that is not a number, such as a string, to a number, the result will also be Nan. This value can cause problems with applications, so it is important to check for Nan ahead of time.

Nan can be detected in Javascript by using the isNaN() function. This function will return true if the value passed to it is Nan, and false if it is not. It is important to note that this function will also return true if the value passed to it is not a number, such as a string or an array. Therefore, it is important to use other methods to check for Nan, such as using the typeof operator to check the type of the value.

How to Check for Nan in Javascript

To check for Nan in Javascript, the most common method used is the “isNan()” function. This function can take one parameter which is generally passed in as the value which is being tested for Nan. Using this function will return a “true” or “false” value, depending on whether or not the value is Nan.

It is important to note that the isNan() function will return true for any value that is not a number, including strings, objects, and undefined values. Therefore, it is important to use this function with caution and to make sure that the value being tested is actually a number before using the isNan() function.

IsNan() Function Explained

The isNan() function takes one argument that is considered to be the “testValue.” The testValue is evaluated and if it can be coerced into a Number type (primitive), the function will return false. If the testValue cannot be coerced into Numbers, then the result will be true. For example, if a user was to perform a isNan() function with an empty string as the argument, the function would return true. The same IsNan() function performed with a string containing only numbers would return false since that particular string can be coerced into a number.

The isNan() function is useful for validating user input. For example, if a user is asked to enter a number, the isNan() function can be used to check if the user input is a valid number. If the isNan() function returns true, then the user input is not a valid number and the user should be asked to enter a valid number.

Benefits of Checking for Nan in Javascript

Checking for Nan can provide a number of benefits as it can help prevent potential errors which might occur due to unexpected results. Specifically, checking for Nan can help ensure that functions and calculations which rely on numerical values do not fail or produce unexpected results if unexpected types are provided as arguments.

In addition, checking for Nan can help improve the overall performance of a program by ensuring that only valid numerical values are used in calculations. This can help reduce the amount of time spent on unnecessary calculations and can help improve the overall speed of the program.

Difference Between Nan and Other Values

The difference between Nan and other values lies in that Nan is explicitly designated as not being a valid number type. This distinction helps as it provides an easy way to identify values that could lead to unforeseen problems down the line. Other numerical types, such as numbers or floats, are all valid values that are supported by Javascript.

Nan is a special type of value that is used to indicate that a value is not a number. It is important to note that Nan is not the same as a null value, which is used to indicate that a value is not present. Nan is used to indicate that a value is not a valid number, while null is used to indicate that a value is not present.

Common Mistakes When Checking for Nan

When working with the isNan() function, there are a few common mistakes to watch out for. First, it’s important to watch out for the difference between Nan and other numerical types. Specifically, when passing arguments into the isNan() function that contain functions or spaces as part of the argument, the result can be interpreted as Nan. Therefore, it’s important to make sure that only arguments which are expected numerical types are passed into the function.

Another common mistake is to forget to use the strict equality operator (===) when comparing the result of the isNan() function. This is because the isNan() function returns a boolean value, and the strict equality operator is necessary to ensure that the result is accurately interpreted. Additionally, it’s important to remember that the isNan() function is case-sensitive, so it’s important to make sure that the argument is in the correct case.

Examples of Checking for Nan

Below are two examples of checking for Nan using the isNan() function. The first example shows an isNan() check on an argument that is expected to pass as true (a string containing only numbers). The next example shows an argument that should fail as true (a text string):

  • Example 1: isNan(“12345”) // Returns False
  • Example 2: isNan(“This Is Text”) // Returns True

It is important to note that the isNan() function is case-sensitive, meaning that it will return false if the argument contains any capital letters. For example, isNan(“ThisIsText”) will return false, while isNan(“This Is Text”) will return true.

Conclusion

In conclusion, checking for Nan in Javascript can be an important part of ensuring that application performance is not compromised by unexpected results. The process of checking for Nan is as simple as using the built-in “isNan()” function. As long as all arguments are expected numerical types and spaces are avoided, this process should be relatively straight forward. With this knowledge, developers should be better equipped to work safely with numeric values in Javascript.

It is also important to note that the isNan() function is not the only way to check for Nan in Javascript. Other methods such as using the typeof operator or comparing the value to itself can also be used. Ultimately, the best method to use will depend on the specific application and the data being used. Regardless of the method chosen, it is important to ensure that Nan values are properly handled in order to maintain application performance.

Anand Das

Anand Das

Anand is Co-founder and CTO of Bito. He leads technical strategy and engineering, and is our biggest user! Formerly, Anand was CTO of Eyeota, a data company acquired by Dun & Bradstreet. He is co-founder of PubMatic, where he led the building of an ad exchange system that handles over 1 Trillion bids per day.

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