A list is a monad

Reminds me on an analogy for a monad I once heard. Not sure if it is correct because I lack the mathematical understanding to verify.

Anyway, a nested To-Do list is (allegedly) a common form of a monad. Say I am trying to clean my whole house. Well, I could have an item for a task like cleaning the kitchen that has each task I need to do in the kitchen in order for the kitchen to be cleaned. I can do the same for the living room, garage, etc..

However, that is mainly for organization purposes. While I may write the tasks in a nested manner, I could very well write each item as just a long flat list of To-Do tasks, and in reality, all the tasks are effectively completed as if they were one large flat list.

Is that kind of what you mean by 'flatMappable'? Nested To-Do lists being flattened and mapped to one large list? As in, a To-Do list of To-Do lists is just a single, larger To-Do list?

Yes, your understanding is correct. It's literally calling map() on an array, followed by a flat().

Sorry, I should have added more context to my post. I edited my post and added a link to the MDN definition of the flatMap function.

Not exactly. The flatMap() operation itself isn’t going to flatten an arbitrarily nested todo list. It just concatenates the lists that are returned after applying the callback to each item.

The monad part is about what happens if you call flatMap() repeatedly. That is, each call to flatMap() is one action, and these actions can be nested without affecting the result.