Function store_get

packages/svelte/src/internal/client/reactivity/store.js:36–80

(store, store_name, stores)

 * @returns {V}
 */
export function store_get(store, store_name, stores) {
	const entry = (stores[store_name] ??= {
		store: null,
		source: mutable_source(undefined),
		unsubscribe: noop
	});

	if (DEV) {
		entry.source.label = store_name;
	}

	// if the component that setup this is already unmounted we don't want to register a subscription
	if (entry.store !== store && !(IS_UNMOUNTED in stores)) {
		entry.unsubscribe();
		entry.store = store ?? null;

		if (store == null) {
			entry.source.v = undefined; // see synchronous callback comment below
			entry.unsubscribe = noop;
		} else {
			var is_synchronous_callback = true;

			entry.unsubscribe = subscribe_to_store(store, (v) => {
				if (is_synchronous_callback) {
					// If the first updates to the store value (possibly multiple of them) are synchronously
					// inside a derived, we will hit the `state_unsafe_mutation` error if we `set` the value
					entry.source.v = v;
				} else {
					set(entry.source, v);
				}
			});

			is_synchronous_callback = false;
		}
	}

	// if the component that setup this stores is already unmounted the source will be out of sync
	// so we just use the `get` for the stores, less performant but it avoids to create a memory leak
	// and it will keep the value consistent
	if (store && IS_UNMOUNTED in stores) {
		return get_store(store);
	}

	return get(entry.source);
}

/**
 * Unsubscribe from a store if it's not the same as the one in the store references container.