50 lines
1.3 KiB
TypeScript
50 lines
1.3 KiB
TypeScript
import { type Writable, writable } from 'svelte/store';
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function isStore(v: unknown): v is Writable<unknown> {
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return v !== null && typeof v === 'object' && 'subscribe' in v && 'set' in v;
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}
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const storeIds: Map<string, ReturnType<typeof createLocalStore>> = new Map();
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const HAS_LOCALSTORAGE = 'localStorage' in globalThis;
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function createLocalStore<T>(key: string, initialValue: T | Writable<T>) {
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let store: Writable<T>;
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if (HAS_LOCALSTORAGE) {
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const localValue = localStorage.getItem(key);
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const value = localValue ? JSON.parse(localValue) : null;
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if (value === null) {
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if (isStore(initialValue)) {
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store = initialValue;
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} else {
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store = writable(initialValue);
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}
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} else {
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store = writable(value);
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}
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} else {
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return isStore(initialValue) ? initialValue : writable(initialValue);
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}
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store.subscribe((value) => {
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localStorage.setItem(key, JSON.stringify(value));
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});
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return {
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subscribe: store.subscribe,
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set: store.set,
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update: store.update
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};
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}
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export default function localStore<T>(key: string, initialValue: T | Writable<T>): Writable<T> {
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if (storeIds.has(key)) return storeIds.get(key) as Writable<T>;
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const store = createLocalStore(key, initialValue);
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storeIds.set(key, store);
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return store;
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}
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