This PR:

• Switches the memoization of incoming arguments back todefaultMemoize for perf atm
  • NOTE: this will require significantly more investigation and consideration. See:
    • [Enhancement] Selector Debugging Tools #279
    • Use provided memoize function for selectors #297 (the actual change that putmemoize() there now)
    • Can't set selector memoization function #298
    • Use provided memoize options in outer memoize call #359
• Adds 3 new experimental memoizers:
  • autotrackMemoizer: uses Proxies and an "autotracking" implementation to determineexactly which fields are accessed in a selector, and only recalculate when those fields get changed
  • weakMapMemoizer: usesWeakMaps to form a tree of cache lookups based on args
  • signalisMemoizer: useshttps://github.com/cafreeman/signalis to try to do something similar to theautotrack approach

There's a good chance that these could go into v4.x, but I'm putting them in a 5.x-based build branch for now.

Status and Tradeoffs

Currently,autotrack andweakMap seem to actually work and pass tests.signalis runs but doesn't memoize properly.

autotrack works well! I can confirm that if you do something liketodos => todos.map(t => t.id), and then flipt.completed, it willnot recalculate. However, it also is definitely slower thandefaultMemoize. The question is whether the slowness is enough to matter in practice. On the flip side, the fact that it can recalculate a lot less often in some cases means that there'd be fewer re-renders.

weakMap is closer in speed todefaultMemoize. Haven't done significant testing on it yet. Seems like there's some amount of multi-size behavior by default, but haven't figured out how that grows over time or gets GC'd.

Resources / inspiration / places I swiped code from:

• Autotrack:
  • https://github.com/simonihmig/tracked-redux
  • https://www.pzuraq.com/blog/how-autotracking-works
  • https://gist.github.com/pzuraq/79bf862e0f8cd9521b79c4b6eccdc4f9
  • https://github.com/lifeart/glimmerx-workshop
  • https://v5.chriskrycho.com/journal/autotracking-elegant-dx-via-cutting-edge-cs/
  • https://github.com/glimmerjs/glimmer-vm/blob/master/packages/%2540glimmer/validator/
• WeakMap:
  • Straight out of the React Cache source:ReactCache.ts
• Signalis:
  • createStore andupdate do not work with frozen objects cafreeman/signalis#53