re: My New Friends filter() and map() VIEW POST


.some and .every are amazing too, also .reduce. All the functors rock. Also Array.from

This is a nifty trick too, pass a Boolean construtor to clean an array of all falsely or holes, return only truthy values.

["", 0, "HEY", , null, -Infinity]
    .filter(Boolean) // => ["Hey"]

Lastly .find is just like filter but returns one value rather than an array.

I think all the functors are based on reduce.

This is functional programming where this expression is preferred over statements like if and for. You will be surprised how much you can get away with.


A functor in FP is the thing that is mapped over (a typeclass with an fmap implementation in Haskell), not the function that gets applied. What you refer to as “functors” are higher-order functions.


Groovy well that's straightend out. 😅


Incredible how there's still things to learn. I will definitely start looking at ways to through in this nifty trick, and that .find too! Thanks!


Looks like I should do a post on JavaScript arrays


Ooh! New toys! I'll have to check them and see what they do.

Code of Conduct Report abuse