Svelte 5 Store to State #svelte #store #typescript

to-state.svelte.ts

// !! This is yet untested
import type { Writable } from 'svelte/store';

export const toState = <T>(store: Writable<T>, initial: T | null = null) => {
	let value = $state<T | null>(initial);

	const stateful = {
		get: () => value,
		set: (newValue: T) => {
			store.set(newValue);
			value = newValue;
		},
		subscribe: (run: (value: T) => void) => {
			const unsubscribeStore = store.subscribe(run);
			return () => unsubscribeStore();
		},
	};

	return stateful;
};