chore(create-storage-sync-feature): wip

libs/ngrx-toolkit/src/lib/storageSync/create-storage-sync-feature.ts

@@ -0,0 +1,91 @@
+import {
+  EmptyFeatureResult,
+  patchState,
+  signalStoreFeature,
+  SignalStoreFeature,
+  SignalStoreFeatureResult,
+  withMethods,
+} from '@ngrx/signals';
+import { inject, PLATFORM_ID } from '@angular/core';
+import { isPlatformServer } from '@angular/common';
+
+export type SyncDriver<State> = {
+  /**
+   * read from Storage(localStorage, sessionStorage, indexedDB)
+   */
+  read(): State | undefined | Promise<State | undefined>;
+
+  /**
+   * write to Storage(localStorage, sessionStorage, indexedDB)
+   */
+  write(): void | Promise<void>;
+
+  /**
+   * clear Storage(localStorage, sessionStorage, indexedDB)
+   */
+  clear(): void | Promise<void>;
+};
+
+export type CreateSyncOptions<State> = {
+  /**
+   * Flag indicating if the store should read from storage on init and write to storage on every state change.
+   *
+   * `true` by default
+   */
+  autoSync?: boolean;
+
+  /**
+   * Function to select that portion of the state which should be stored.
+   *
+   * Returns the whole state object by default
+   */
+  select?: (state: State) => Partial<State>;
+};
+
+const createStorageSyncFeatureStub: Pick<
+  SignalStoreFeatureResult,
+  'methods'
+>['methods'] = {
+  read: () => void true,
+  write: () => void true,
+  clear: () => void true,
+};
+
+export function createStorageSyncFeature<
+  State extends object,
+  Input extends SignalStoreFeatureResult
+>(
+  driverFactory: () => SyncDriver<State>,
+  options: CreateSyncOptions<State>
+): SignalStoreFeature<Input, EmptyFeatureResult> {
+  const { autoSync = true, select = (state: State) => state } = options;
+
+  return signalStoreFeature(
+    withMethods((store, platformId = inject(PLATFORM_ID)) => {
+      if (isPlatformServer(platformId)) {
+        return createStorageSyncFeatureStub;
+      }
+
+      const driver = driverFactory();
+
+      return {
+        read: async () => {
+          const value = await driver.read();
+
+          if (value) {
+            patchState(store, select(value));
+          }
+          // todo value typed check
+        },
+
+        write: async () => {
+          // todo
+        },
+
+        clear: async () => {
+          // todo
+        },
+      };
+    })
+  );
+}

libs/ngrx-toolkit/src/lib/storageSync/with-indexeddb.ts

@@ -134,6 +134,9 @@ export function withIndexedDB<State extends object>(): WithIndexedDBFn<State> {
           envInjector = inject(EnvironmentInjector)
         ) {
           if (isPlatformServer(platformId)) {
+            console.warn(
+              `'withStorageSync' provides non-functional implementation due to server-side execution`
+            );
             return;
           }