Supabase not updated if there are no observers

[juanmigdr]

I am using LegendState V3 with the Supabase plugin and I was having an issue where I was doing a .set() and the data was only being stored locally and not in the DB. After a lot of troubleshooting I found out that if I do not have an observer listening to the changes, these are not updated in Supabase. Here is my configuration:

export const generateId = () => uuidv4();

export const customSynced = configureSynced(syncedSupabase, {
  persist: {
    plugin: observablePersistAsyncStorage({
      AsyncStorage,
    }),
  },
  generateId,
  supabase,
  changesSince: "last-sync",
  fieldCreatedAt: "created_at",
  fieldUpdatedAt: "updated_at",
  fieldDeleted: 'deleted'
});

Here is the table I am updating:

import { batch, observable } from "@legendapp/state";
import { customSynced, supabase, generateId } from "../utils/SupaLegend";
import { exams$ } from "./examsState";
import { use$ } from "@legendapp/state/react";
import { observe } from "@legendapp/state";

export const chapters$ = observable(
  customSynced({
    supabase,
    initial: {},
    collection: "chaps",
    select: (from) =>
      from
        .select("id,blocks,selected_block_idx,created_at,updated_at,deleted")
        .order("created_at", { ascending: false }),
    actions: ["read", "create", "update", "delete"],
    realtime: true,    persist: {
      name: "chapters",
      retrySync: true,
    },
    retry: {
      infinite: true,
    },
    onError(error, params) {
      console.log(error);
    },
    onSaved(params) {
      console.log("SV");
    },
    syncMode: "auto",
  })
);

export const addChapter = (examId: string) => {
  const chapterId = generateId();
  chapters$[chapterId].assign({
      id: chapterId,
      blocks: [],
      selected_block_idx: 0,
  });
};

Since I have nothing observing these, the only way to fix the issue was to add the following at the bottom:

observe(() => {
  chapters$.get();
  console.log("Chapters updated:");
});

Is this intended? If so:

• Why?
• Where is it documented?

[jmeistrich]

Yes, it's intended, though I very much understand how it's confusing. It's documented here but we may need to repeat that in all the plugin pages...

The reason is that it's very useful to be able to define how an observable syncs itself when accessed, without actually syncing it. In Bravely for example, we set up sync for hundreds of different observables, and then individual pages access some subset of them. We don't want to immediately call hundreds of server functions, but to update them on demand while the user navigates around between pages.

However! Doing a set should trigger a sync followed by committing the save to the server. We have some tests for that:

legend-state/tests/computed-persist.test.ts

Line 262 in 751a565

test('set not called until loaded first', async () => {

But is that not working in supabase for some reason? Can you make sure you're on the latest beta version and confirm in the network logs that calling set doesn't trigger the supabase sync or the update?