svelte/src/store/index-server.js

Cybernetically enhanced web apps

/** @import { Readable, Writable } from './public.js' */
import { get, writable } from './shared/index.js';

export { derived, get, readable, readonly, writable } from './shared/index.js';

/**
 * @template V
 * @overload
 * @param {() => V} get
 * @param {(v: V) => void} set
 * @returns {Writable<V>}
 */
/**
 * @template V
 * @overload
 * @param {() => V} get
 * @returns {Readable<V>}
 */
/**
 * Create a store from a function that returns state, and (to make a writable store), an
 * optional second function that sets state.
 *
 * ```ts
 * import { toStore } from 'svelte/store';
 *
 * let count = $state(0);
 *
 * const store = toStore(() => count, (v) => (count = v));
 * ```
 * @template V
 * @param {() => V} get
 * @param {(v: V) => void} [set]
 * @returns {Writable<V> | Readable<V>}
 */
export function toStore(get, set) {
	const store = writable(get());

	if (set) {
		return {
			set,
			update: (fn) => set(fn(get())),
			subscribe: store.subscribe
		};
	}

	return {
		subscribe: store.subscribe
	};
}

/**
 * @template V
 * @overload
 * @param {Writable<V>} store
 * @returns {{ current: V }}
 */
/**
 * @template V
 * @overload
 * @param {Readable<V>} store
 * @returns {{ readonly current: V }}
 */
/**
 * Convert a store to an object with a reactive `current` property. If `store`
 * is a readable store, `current` will be a readonly property.
 *
 * ```ts
 * import { fromStore, get, writable } from 'svelte/store';
 *
 * const store = writable(0);
 *
 * const count = fromStore(store);
 *
 * count.current; // 0;
 * store.set(1);
 * count.current; // 1
 *
 * count.current += 1;
 * get(store); // 2
 * ```
 * @template V
 * @param {Writable<V> | Readable<V>} store
 */
export function fromStore(store) {
	if ('set' in store) {
		return {
			get current() {
				return get(store);
			},
			set current(v) {
				store.set(v);
			}
		};
	}

	return {
		get current() {
			return get(store);
		}
	};
}