[storage] signal is not updated during hydration when doing SSR or SSG

[mb21]

Describe The Problem To Be Solved

Reproduce by creating a new solid-start project from the bare template with SSR and change the line in Counter.tsx to:

const [count, setCount] = makePersisted(createSignal(0));

(Sorry I couldn't find a stackblitz template with solid-start.)

If you increase the counter and then reload the page, the counter isn't rendered and you get in the console:

Counter.tsx:7 Unable to find DOM nodes for hydration key: 0-0-0-0-0-0-0-0-0-1-0-0-0-0-2-1-0-0-2-1

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Similarly, using Astro's client:load directive (which does server-side render or generate the HTML in SSG-mode), on page-load the counter is always 0.

Suggest A Solution

While it's unavoidable that the initial HTML contains 0 (since we cannot know the value of localStorage on the server), ideally storage would update the signal during or after hydration to read out the value from localStorage.