What are the differences between functors and monads in programming?

What are the differences between functors and monads in programming?

Functors and monads are both design patterns in functional programming. A functor is a type that can be mapped over, allowing you to apply a function to values wrapped in a context. A monad, on the other hand, is a more powerful abstraction that allows for chaining operations while managing side effects.

Can you give me an example of a functor?

Sure! In JavaScript, an array is a functor. You can use the map method to apply a function to each element in the array. For example, const numbers = [1, 2, 3]; const doubled = numbers.map(x => x * 2); results in [2, 4, 6].

What about an example of a monad?

A common example of a monad is the Promise in JavaScript. Promises allow you to handle asynchronous operations. You can chain .then() calls to process the result of a promise, like this: fetch(url).then(response => response.json()).then(data => console.log(data));.

How do functors and monads relate to each other?

Functors can be seen as a simpler case of monads. Every monad is a functor, but not every functor is a monad. Monads provide additional structure that allows for more complex operations, including handling side effects and chaining.