When obtaining a value that was set before the current component initializes, it is possible to first read an undefined value from the store. Eventually the value is set and the subscribers then receive the correct value.

To reproduce this, set a local value in the background process:

// background.ts
chrome.runtime.onInstalled.addListener(() => {
	chrome.storage.local.set({"test": 1337})
}

Then in your popup component, immediately subsribe to the value:

<script lang="ts">
    import {chromeStorageLocal} from "svelte-chrome-storage/dist/chrome-storage-store-adapter"

    let testStore = chromeStorageLocal<number>("test")
    $: console.log("$testStore:", $testStore)
</script>

In the console of the popup I get

index.js:6 $testStore: undefined
index.js:6 $testStore: 1337

I ran into this when attempting to do a comparison on a store value and it was not as expected.

I did confirm that if you check the value using setTimeout after a short wait, the first read on the value is correct, indicating that it is a timing/initialization issue and not an issue with the first read per-se.

This library appeared to be exactly what I was looking for (and trying to implement myself), but as I tried to use it I ran into issues.

My goal is to keep my store strongly typed and provide setters for each field that should be editable. Something like the following:

const Key = "settings"

type Settings = {
	recording: boolean;
	recordTabId: string;
	onSettingsPage: boolean;
	settingsUrl: string;
}

function settingsStore() {
	// Causes more issues
	// const { subscribe, update } = chromeStorageLocal<Settings>(Key)

	const settings = chromeStorageLocal<Settings>(Key)

	return {
		subscribe: settings.subscribe,
		startRecording: () => settings.update(state => ({...state, recording: true})),
		stopRecording: () => settings.update(state => ({...state, recording: false})),
		setRecordTabId: (id: string) => settings.update(state => ({...state, recordTabId: id})),
		clearRecordTabId: () => settings.update(state => ({...state, recordTabId: ""})),
	}
}

Doing this, I run into issues where this is not defined when subscribing. If I pull the subscribe and update methods off of chromeStorageLocal, I run into similar issues when calling update from my setters (i.e. update(...) instead of settings.update(...)).

I was going to try extending the ChromeStorageStoreAdapter class, but it is not exported.

Likely this approach just is not compatible with the library. And assuming it isn't and isn't meant to be, I'm wondering if you have any other guidance on a way to type the store with an object and allow callers to set individual keys without having to pass back in the entire object themselves.

I'm trying to avoid doing the following from the callers:

let settingsStore = chromeStorageLocal<Settings>(Key)
settingsStore.update(state => ({...state, recording: false}))

I'm doing the following import as instructed by the README:

import {chromeStorageLocal} from "svelte-chrome-storage"

But chromeStorageLocal has type any because of the error:

Could not find a declaration file for module 'svelte-chrome-storage

Things work fine when importing from the dist folder:

import {chromeStorageLocal} from "svelte-chrome-storage/dist/chrome-storage-store-adapter"

vscode is producing the error.