fix: reduce the number of API requests when changing route

[martabal]

Reduce the number of API requests when changing route by storing the already stored value to a store. (maybe there's a better way with svelte 5?)

Example with navigating from /photos to /utilities

Before	After
	No request

[alextran1502]

We probably should use the rune syntax for these since store syntax will be deprecated in the future iirc

[danieldietzler]

Yup, this should be some global state :)

[martabal]

@alextran1502 I don't think stores will be deprecated

@danieldietzler What's the svelte way for global state (classes, functions...)? I didn't find any example in Immich codebase.

[danieldietzler]

#14662 could be a good inspiration?

[michelheusschen]

Stores are indeed not deprecated. In this situation you can just replace writable() with $state() and make sure the file ends with .svelte or .svelte.ts

We do have to be careful about persisting state globally, because a user could log in with a different account. Data can also become stale after a certain period.

This PR also fixes #14509

[alextran1502]

The userInteraction global state should be cleared when logging out, correct?

[martabal]

The userInteraction global state should be cleared when logging out, correct?

Indeed!

[danieldietzler]

Code looks good to me

[danieldietzler]

You could completely drop this variable and replace it with the global userInteraction.recentAlbums state

[martabal]

Do you mean dropping let albums: AlbumResponseDto[] = $state([]); in favor of using only userInteraction.recentAlbums? If so, you have to wrap the each section in a {#if userInteraction.recentAlbums} because userInteraction.recentAlbums can be undefined. What do you prefer?

[danieldietzler]

Can it be undefined? You'd still set it in onMount if it's undefined, and onMount finishes before it actually mounts, right?

[danieldietzler]

Or is my svelte knowledge lacking here? 😅

[martabal]

Yes, technically it can't be undefined, but Svelte isn't smart enough to figure that out. It only uses the type definition

interface UserInteractions {
  recentAlbums?: AlbumResponseDto[];
  versions?: ServerVersionHistoryResponseDto[];
  aboutInfo?: ServerAboutResponseDto;
  serverInfo?: ServerStorageResponseDto;
}

[danieldietzler]

Ah gotcha. Then I'd prefer keeping that extra variable as well