Functors
Functors are a fundamental concept in functional programming and category theory that represent a mapping between categories, preserving structure. In programming, a functor is typically a type that can be mapped over, such as lists or optional values, allowing functions to be applied to wrapped values without unwrapping them. This enables operations like transformation and composition in a pure, side-effect-free manner.
Developers should learn functors when working with functional programming languages like Haskell, Scala, or JavaScript (with libraries like Ramda) to handle data transformations in a declarative and composable way. They are essential for managing side effects, error handling (e.g., with Maybe/Option types), and building abstractions in functional architectures, such as in data processing pipelines or reactive programming.