Focusable atoms (optics for this lib)

Hello,

Interesting library!

Would it be possible for you to provide utilities for using this in conjunction with a optics library? My idea for a pretty nice api would be:

const bigAtom: WritableAtom<{myKey: number[]}> = atom({myKey: [1,2,3]})
const focusedAtom: WritableAtom<number> = bigAtom.focus(optic => optic.prop('myKey').index(0))

Or even:

const bigAtom: WritableAtom<{myKey: 10}> = atom({myKey: 10})
const focusedAtom: WritableAtom<number> = bigAtom.prop('myKey').index(0)

The optics library I like is https://github.com/akheron/optics-ts

The idea is that if any of the focused atoms are “set”, then the big atom is updated, leading to a update to the focused atom.

[merisbahti]

Nope! I think this is the way it’s supposed to work.

If an optional focus (Prism) does not have a value, the setter does nothing.

According to the optics-ts docs (which is used here), here’s the explaination of the optional: https://akheron.github.io/optics-ts/reference-mc/#optional

Create a prism that focuses on the non-undefined subtype of A.

If I’ve understood it correctly, it means that it only focuses on the non-undefined case - if it’s another case, then it does nothing. In this case, it’s undefined, so it does nothing!

I hope that was of help, and if I can assist with something else or elborate further, please ask 😄

[merisbahti]

Looks about right (typing it will be interesting, since some optics are ReadOnly, and some are removable).

Thanks, I think this resolves my issue.