1 files changed, 102 insertions, 0 deletions
diff --git a/apps/web-shared/src/lib/persistent-store.ts b/apps/web-shared/src/lib/persistent-store.ts
new file mode 100644
index 0000000..922f3ab
--- /dev/null
+++ b/apps/web-shared/src/lib/persistent-store.ts
@@ -0,0 +1,102 @@
+import { writable as _writable, readable as _readable, } from "svelte/store";
+import type { Writable, Readable, StartStopNotifier } from "svelte/store";
+
+enum StoreType {
+    SESSION = 0,
+    LOCAL = 1
+}
+
+interface StoreOptions {
+    store?: StoreType;
+}
+
+const default_store_options = {
+    store: StoreType.SESSION
+} as StoreOptions;
+
+interface WritableStore<T> {
+    name: string,
+    initialState: T,
+    options?: StoreOptions
+}
+
+interface ReadableStore<T> {
+    name: string,
+    initialState: T,
+    callback: StartStopNotifier<any>,
+    options?: StoreOptions
+}
+
+function get_store(type: StoreType): Storage {
+    switch (type) {
+        case StoreType.SESSION:
+            return window.sessionStorage;
+        case StoreType.LOCAL:
+            return window.localStorage;
+    }
+}
+
+function prepared_store_value(value: any): string {
+    try {
+        return JSON.stringify(value);
+    } catch (e) {
+        console.error(e);
+        return "__INVALID__";
+    }
+}
+
+function get_store_value<T>(options: WritableStore<T> | ReadableStore<T>): any {
+    try {
+        const storage = get_store(options.options.store);
+        const value = storage.getItem(options.name);
+        if (!value) return false;
+        return JSON.parse(value);
+    } catch (e) {
+        console.error(e);
+        return { __INVALID__: true };
+    }
+}
+
+function hydrate<T>(store: Writable<T>, options: WritableStore<T> | ReadableStore<T>): void {
+    const value = get_store_value<T>(options);
+    if (value && store.set) store.set(value);
+}
+
+function subscribe<T>(store: Writable<T> | Readable<T>, options: WritableStore<T> | ReadableStore<T>): void {
+    const storage = get_store(options.options.store);
+    if (!store.subscribe) return;
+    store.subscribe((state: any) => {
+        storage.setItem(options.name, prepared_store_value(state));
+    });
+}
+
+function writable_persistent<T>(options: WritableStore<T>): Writable<T> {
+    if (options.options === undefined) options.options = default_store_options;
+    console.log("Creating writable store with options: ", options);
+    const store = _writable<T>(options.initialState);
+    hydrate(store, options);
+    subscribe(store, options);
+    return store;
+}
+
+function readable_persistent<T>(options: ReadableStore<T>): Readable<T> {
+    if (options.options === undefined) options.options = default_store_options;
+    console.log("Creating readable store with options: ", options);
+    const store = _readable<T>(options.initialState, options.callback);
+    // hydrate(store, options);
+    subscribe(store, options);
+    return store;
+}
+
+export {
+    writable_persistent,
+    readable_persistent,
+    StoreType
+};
+
+export type {
+    WritableStore,
+    ReadableStore,
+    StoreOptions
+};
+