Handle Errors in Functional Way
3 min read
Either type and the
What is the
Functional programming is a programming paradigm that emphasizes the use of pure functions and immutable data. It is based on the idea that programs can be thought of as a series of transformations on data, and that these transformations can be composed in a modular way to create complex programs.
Either type is an important tool in functional programming, as it allows developers to handle errors and exceptions in a way that is composable and easy to understand. It is often used in combination with other functional programming concepts, such as monads and monoids, to create powerful and expressive error-handling systems.
Either type can be implemented manually or through the use of libraries. One popular library for working with
Here is an example of using the
Either type from the
In this example, we define two functions,
multiply, that return a Monet
Either object. The
divide function returns a
Left either with an error if the denominator is 0, and a
Right either with the result of the division if the denominator is non-zero. The
multiply function works similarly.
We then use the
flatMap method on the result of
divide(4, 2) to pass the result (2) to the
multiply function. The
flatMap method allows us to easily compose these two operations, as it will only pass the value to the next function if the previous function returned a
Finally, we use the
cata method on the result of the chained operation to either log the success value or print the error, depending on the type of either returned.
This demonstrates how the
Either solution can be easily composed, as we can chain multiple operations together using the
Comparison with try/catch
Now let's compare the
Either type with the
Here is an example using
try/catch for dividing and multiplying numbers:
In this example, the
multiply functions throw errors if certain conditions are met. The
try/catch statement is used to catch any errors that may be thrown during the execution of these functions.
So, how do
try/catch compare? One advantage of
Either is that it allows developers to clearly distinguish between successful and failed operations. In the
try/catch example, it is not immediately clear.
Provides a clear separation between successful and failed operations
Allows for easy composition of multiple error-handling operations
Can be implemented manually or through the use of libraries, such as Monet
Requires additional code to be written in order to use the Either type
May be more difficult for developers who are not familiar with functional programming concepts
Familiar to most developers
Can lead to verbose and hard-to-read code, especially when multiple try/catch blocks are nested
Does not provide a clear separation between successful and failed operations
Does not support easy composition of multiple error-handling operations
In my opinion, the
Either version is more suitable for use in a larger application where the component may be used by other components. This is because
Either allows for easy composition of different components and provides a clear indication of success or failure. On the other hand,
Try/Catch may be more appropriate for use in a component that is not intended to be reused by other components.