Recommended listening during read: https://open.spotify.com/track/1vBb916w3u10h8U87QJ1GN Tl;dr We can convert any indexable data structure into its function form to achieve laziness. Formally, there’s an isomorphism from any Representable Functor to Reader. Gist is here: https://gist.github.com/DrBoolean/9b951c1c2cb225be9c289b0a2239132f Prereq I boldly use words like curry (functions that take 1 arg at a time), isomorphism (a lossless…

Recommended listening during read: https://open.spotify.com/track/29h3NmtIybnBQDJiTM8TuB Tl;dr Pure functional data structures allow us to focus on the composition of complex, effectful workflows through reasoning and interchangeable instances. We can stub functions to return these types, get the composition right, then circle back to implement the functions. Also, traverse kicks ass. Prereq To get…

Recommended listening during read: spotify:track:3bCmDqflFBHijgJfvtqev5 Tl;dr Lenses are pretty useful to dig deep into data structures and make changes in a pure functional way. Immutable.js and lenses are a great fit because they provide us with a universal api for working with built in and immutable data structures. We can also…

Tl;dr The tl;dr is that we can take functions that are concrete in their output, combine them with concat, and contramap over their input. This allows us to do cool things like combine filter predicates and sort comparisons while providing flexibility on their arguments. …

What’s the problem When working with ramda or lodash-fp, one may run into some rather cryptic error messages. When trying to console.log a function we’re presented with the guts of some internal curry or compose implementation that tells us nothing. …