fix timestamps on rehydrate

src/app/core/data-services/request-cache.effects.ts

@@ -0,0 +1,36 @@
+import { Injectable } from "@angular/core";
+import { Actions, Effect } from "@ngrx/effects";
+import { ResetRequestCacheTimestampsAction } from "../cache/request-cache.actions";
+import { Store } from "@ngrx/store";
+import { RequestCacheState } from "../cache/request-cache.reducer";
+import { ObjectCacheActionTypes } from "../cache/object-cache.actions";
+
+@Injectable()
+export class RequestCacheEffects {
+
+  constructor(
+    private actions$: Actions,
+    private store: Store<RequestCacheState>
+  ) { }
+
+  /**
+   * When the store is rehydrated in the browser, set all cache
+   * timestamps to "now", because the time zone of the server can
+   * differ from the client.
+   *
+   * This assumes that the server cached everything a negligible
+   * time ago, and will likely need to be revisited later
+   *
+   * This effect should listen for StoreActionTypes.REHYDRATE,
+   * but can't because you can only have one effect listen to
+   * an action atm. Github issue:
+   * https://github.com/ngrx/effects/issues/87
+   *
+   * It's listening for ObjectCacheActionTypes.RESET_TIMESTAMPS
+   * instead, until there's a solution.
+   */
+  @Effect() fixTimestampsOnRehydrate = this.actions$
+    .ofType(ObjectCacheActionTypes.RESET_TIMESTAMPS)
+    .map(() => new ResetRequestCacheTimestampsAction(new Date().getTime()));
+
+}