Performance issue: updateStore blocks rendering during diffing with large arrays in reactive store

[aralroca]

While fixing this issue, I noticed another bug (that was happening and is still happening).

When diffing on SPA (or server actions), the actual updateStore function is very slow and blocks rendering badly.

brisa/packages/brisa/src/utils/rpc/resolve-rpc/index.ts

Lines 24 to 32 in c172d4c

	function updateStore(entries: [string, any][]) {
	// Store WITH web components signals, so we need to notify the subscribers
	// to keep the reactivity
	if (store) {
	for (const [key, value] of entries) store.set(key, value);
	}
	// Store WITHOUT web components signals
	else $window._S = entries;
	}

By doing store.set several times, it triggers notifications to update reactively, because it is a reactive map. We need to investigate what is the part that takes the longest, and then try to do this code in a non-blocking way.

It can be reproduced when you have large arrays in the store, which after deserialization always detects it as a new field in the store and is updated even if it is the same value.

[aralroca]

Another thing that consume a lot of milliseconds is recalculating styles:

brisa/packages/brisa/src/utils/brisa-element/index.ts

Line 209 in 01a994a

for (const rule of sheet.cssRules) css.push(rule.cssText);