NodeRedux state container for ESP devices

[shubham-sri]

Fixes #3420

• This PR is for the dev branch rather than for the release branch.
• This PR is compliant with the other contributing guidelines as well (if not, please describe why).
• I have thoroughly tested my contribution.
• The code changes are reflected in the documentation at docs/*.

[nwf]

Thank you for your contribution.

This feels very... heavy? Enterprise-y? for an embedded system. Just picking on one example, constructing the first error message in assertReducerShape, even with an empty key k will consume 295 bytes of RAM, credibly between .5% and 1% of the application's initial available heap!

The more idiomatic approach in Lua is to use its OOish facilities, specifically, table lookup (. or the : sugar) and function call as message send. While you could do that inside your store's reducer function to avoid the if/elseif/else chains, it's no less flexible or compositional to instead pass the store itself as a table to the would-be message sources and have them send messages by invoking particular fields. The use of metatables even affords opportunity for "unknown message" handling, should that be useful. If isolation is desired (though it is often less of a concern with the size of applications that fit in ESPs), the store methods can close over the mutable state rather than holding it in the store table itself (though this is not without its costs: the store methods become closures rather than static function references).

[shubham-sri]

Thank you for your contribution.

This feels very... heavy? Enterprise-y? for an embedded system. Just picking on one example, constructing the first error message in assertReducerShape, even with an empty key k will consume 295 bytes of RAM, credibly between .5% and 1% of the application's initial available heap!

The more idiomatic approach in Lua is to use its OOish facilities, specifically, table lookup (. or the : sugar) and function call as message send. While you could do that inside your store's reducer function to avoid the if/elseif/else chains, it's no less flexible or compositional to instead pass the store itself as a table to the would-be message sources and have them send messages by invoking particular fields. The use of metatables even affords opportunity for "unknown message" handling, should that be useful. If isolation is desired (though it is often less of a concern with the size of applications that fit in ESPs), the store methods can close over the mutable state rather than holding it in the store table itself (though this is not without its costs: the store methods become closures rather than static function references).

Hey @nwf, thank you for the nice suggestion

The reducer function is created by the end-user so for more flexibility I have to add if/elseif/else chains, and this same is used in Redux.

And assertReducerShape can be optimized, I'm looking to solve it in an efficient way.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.