Add State Provider Framework (#6640)

* Add StateDefinition

Add a class for encapsulation information about state
this will often be for a domain but creations of this will
exist outside of a specific domain, hence just the name State.

* Add KeyDefinition

This adds a type that extends state definition into another sub-key
and forces creators to define the data that will be stored and how
to read the data that they expect to be stored.

* Add key-builders helper functions

Adds to function to help building keys for both keys scoped
to a specific user and for keys scoped to global storage.

Co-authored-by: Matt Gibson <MGibson1@users.noreply.github.com>

* Add updates$ stream to existing storageServices

Original commit by Matt: 823d9546fe
Co-authored-by: Matt Gibson <MGibson1@users.noreply.github.com>

* Add fromChromeEvent helper

Create a helper that creats an Observable from a chrome event
and removes the listener when the subscription is completed.

* Implement `updates$` property for chrome storage

Use fromChromeEvent to create an observable from chrome
event and map that into our expected shape.

* Add GlobalState Abstractions

* Add UserState Abstractions

* Add Default Implementations of User/Global state

Co-authored-by: Matt Gibson <MGibson1@users.noreply.github.com>

* Add Barrel File for state

Co-authored-by: Matt Gibson <MGibson1@users.noreply.github.com>

* Fix ChromeStorageServices

* Rework fromChromeEvent

Rework fromChromeEvent so we have to lie to TS less and
remove unneeded generics. I did this by caring less about
the function and more about the parameters only.

Co-authored-by: Matt Gibson <MGibson1@users.noreply.github.com>

* Fix UserStateProvider Test

* Add Inner Mock & Assert Calls

* Update Tests to use new keys

Use different key format

* Prefer returns over mutations in update

* Update Tests

* Address PR Feedback

* Be stricter with userId parameter

* Add Better Way To Determine if it was a remove

* Fix Web & Browser Storage Services

* Fix Desktop & CLI Storage Services

* Fix Test Storage Service

* Use createKey Helper

* Prefer implement to extending

* Determine storage location in providers

* Export default providers publicly

* Fix user state tests

* Name tests

* Fix CLI

* Prefer Implement In Chrome Storage

* Remove Secure Storage Option

Also throw an exception for subscribes to the secure storage observable.

* Update apps/browser/src/platform/browser/from-chrome-event.ts

Co-authored-by: Oscar Hinton <Hinton@users.noreply.github.com>

* Enforce state module barrel file

* Fix Linting Error

* Allow state module import from other modules

* Globally Unregister fromChromeEvent Listeners

Changed fromChromeEvent to add its listeners through the BrowserApi, so that
they will be unregistered when safari closes.

* Test default global state

* Use Proper Casing in Parameter

* Address Feedback

* Update libs/common/src/platform/state/key-definition.ts

Co-authored-by: Oscar Hinton <Hinton@users.noreply.github.com>

* Add `buildCacheKey` Method

* Fix lint errors

* Add Comment

Co-authored-by: Oscar Hinton <Hinton@users.noreply.github.com>

* Use Generic in callback parameter

* Refactor Out DerivedStateDefinition

* Persist Listener Return Type

* Add Ticket Link

---------

Co-authored-by: Matt Gibson <MGibson1@users.noreply.github.com>
Co-authored-by: Matt Gibson <mgibson@bitwarden.com>
Co-authored-by: Oscar Hinton <Hinton@users.noreply.github.com>

.eslintrc.json

@@ -100,6 +100,19 @@
                   "./libs/importer/**/*",
                   "./libs/exporter/**/*"
                 ]
+              },
+              {
+                // avoid import of unexported state objects
+                "target": [
+                  "!(libs)/**/*",
+                  "libs/!(common)/**/*",
+                  "libs/common/!(src)/**/*",
+                  "libs/common/src/!(platform)/**/*",
+                  "libs/common/src/platform/!(state)/**/*"
+                ],
+                "from": ["./libs/common/src/platform/state/**/*"],
+                // allow module index import
+                "except": ["**/state/index.ts"]
               }
             ]
           }
@@ -179,17 +192,23 @@
     },
     {
       "files": ["apps/browser/src/**/*.ts", "libs/**/*.ts"],
-      "excludedFiles": "apps/browser/src/autofill/{content,notification}/**/*.ts",
+      "excludedFiles": [
+        "apps/browser/src/autofill/{content,notification}/**/*.ts",
+        "apps/browser/src/**/background/**/*.ts", // It's okay to have long lived listeners in the background
+        "apps/browser/src/platform/background.ts"
+      ],
       "rules": {
         "no-restricted-syntax": [
           "error",
           {
-            "message": "Using addListener in the browser popup produces a memory leak in Safari, use `BrowserApi.messageListener` instead",
-            "selector": "CallExpression > [object.object.object.name='chrome'][object.object.property.name='runtime'][object.property.name='onMessage'][property.name='addListener']"
+            "message": "Using addListener in the browser popup produces a memory leak in Safari, use `BrowserApi.addListener` instead",
+            // This selector covers events like chrome.storage.onChange & chrome.runtime.onMessage
+            "selector": "CallExpression > [object.object.object.name='chrome'][property.name='addListener']"
           },
           {
-            "message": "Using addListener in the browser popup produces a memory leak in Safari, use `BrowserApi.storageChangeListener` instead",
-            "selector": "CallExpression > [object.object.object.name='chrome'][object.object.property.name='storage'][object.property.name='onChanged'][property.name='addListener']"
+            "message": "Using addListener in the browser popup produces a memory leak in Safari, use `BrowserApi.addListener` instead",
+            // This selector covers events like chrome.storage.local.onChange
+            "selector": "CallExpression > [object.object.object.object.name='chrome'][property.name='addListener']"
           }
         ]
       }

apps/browser/src/platform/browser/browser-api.ts

@@ -193,6 +193,9 @@ export class BrowserApi {
   }
 
   static async onWindowCreated(callback: (win: chrome.windows.Window) => any) {
+    // FIXME: Make sure that is does not cause a memory leak in Safari or use BrowserApi.AddListener
+    // and test that it doesn't break.
+    // eslint-disable-next-line no-restricted-syntax
     return chrome.windows.onCreated.addListener(callback);
   }
 
@@ -220,8 +223,10 @@ export class BrowserApi {
 
   // Keep track of all the events registered in a Safari popup so we can remove
   // them when the popup gets unloaded, otherwise we cause a memory leak
-  private static registeredMessageListeners: any[] = [];
-  private static registeredStorageChangeListeners: any[] = [];
+  private static trackedChromeEventListeners: [
+    event: chrome.events.Event<(...args: unknown[]) => unknown>,
+    callback: (...args: unknown[]) => unknown
+  ][] = [];
 
   static messageListener(
     name: string,
@@ -231,13 +236,7 @@ export class BrowserApi {
       sendResponse: any
     ) => boolean | void
   ) {
-    // eslint-disable-next-line no-restricted-syntax
-    chrome.runtime.onMessage.addListener(callback);
-
-    if (BrowserApi.isSafariApi && !BrowserApi.isBackgroundPage(window)) {
-      BrowserApi.registeredMessageListeners.push(callback);
-      BrowserApi.setupUnloadListeners();
-    }
+    BrowserApi.addListener(chrome.runtime.onMessage, callback);
   }
 
   static messageListener$() {
@@ -246,44 +245,67 @@ export class BrowserApi {
         subscriber.next(message);
       };
 
-      BrowserApi.messageListener("message", handler);
+      BrowserApi.addListener(chrome.runtime.onMessage, handler);
 
-      return () => {
-        chrome.runtime.onMessage.removeListener(handler);
-
-        if (BrowserApi.isSafariApi) {
-          const index = BrowserApi.registeredMessageListeners.indexOf(handler);
-          if (index !== -1) {
-            BrowserApi.registeredMessageListeners.splice(index, 1);
-          }
-        }
-      };
+      return () => BrowserApi.removeListener(chrome.runtime.onMessage, handler);
     });
   }
 
   static storageChangeListener(
     callback: Parameters<typeof chrome.storage.onChanged.addListener>[0]
   ) {
-    // eslint-disable-next-line no-restricted-syntax
-    chrome.storage.onChanged.addListener(callback);
+    BrowserApi.addListener(chrome.storage.onChanged, callback);
+  }
+
+  /**
+   * Adds a callback to the given chrome event in a cross-browser platform manner.
+   *
+   * **Important:** All event listeners in the browser extension popup context must
+   * use this instead of the native APIs to handle unsubscribing from Safari properly.
+   *
+   * @param event - The event in which to add the listener to.
+   * @param callback - The callback you want registered onto the event.
+   */
+  static addListener<T extends (...args: readonly unknown[]) => unknown>(
+    event: chrome.events.Event<T>,
+    callback: T
+  ) {
+    event.addListener(callback);
 
     if (BrowserApi.isSafariApi && !BrowserApi.isBackgroundPage(window)) {
-      BrowserApi.registeredStorageChangeListeners.push(callback);
+      BrowserApi.trackedChromeEventListeners.push([event, callback]);
       BrowserApi.setupUnloadListeners();
     }
   }
 
+  /**
+   * Removes a callback from the given chrome event in a cross-browser platform manner.
+   * @param event - The event in which to remove the listener from.
+   * @param callback - The callback you want removed from the event.
+   */
+  static removeListener<T extends (...args: readonly unknown[]) => unknown>(
+    event: chrome.events.Event<T>,
+    callback: T
+  ) {
+    event.removeListener(callback);
+
+    if (BrowserApi.isSafariApi && !BrowserApi.isBackgroundPage(window)) {
+      const index = BrowserApi.trackedChromeEventListeners.findIndex(([_event, eventListener]) => {
+        return eventListener == callback;
+      });
+      if (index !== -1) {
+        BrowserApi.trackedChromeEventListeners.splice(index, 1);
+      }
+    }
+  }
+
   // Setup the event to destroy all the listeners when the popup gets unloaded in Safari, otherwise we get a memory leak
   private static setupUnloadListeners() {
     // The MDN recommend using 'visibilitychange' but that event is fired any time the popup window is obscured as well
     // 'pagehide' works just like 'unload' but is compatible with the back/forward cache, so we prefer using that one
     window.onpagehide = () => {
-      for (const callback of BrowserApi.registeredMessageListeners) {
-        chrome.runtime.onMessage.removeListener(callback);
-      }
-
-      for (const callback of BrowserApi.registeredStorageChangeListeners) {
-        chrome.storage.onChanged.removeListener(callback);
+      for (const [event, callback] of BrowserApi.trackedChromeEventListeners) {
+        event.removeListener(callback);
       }
     };
   }

apps/browser/src/platform/browser/from-chrome-event.spec.ts

@@ -0,0 +1,103 @@
+import { fromChromeEvent } from "./from-chrome-event";
+
+describe("fromChromeEvent", () => {
+  class FakeEvent implements chrome.events.Event<(arg1: string, arg2: number) => void> {
+    listenerWasAdded: boolean;
+    listenerWasRemoved: boolean;
+    activeListeners: ((arg1: string, arg2: number) => void)[] = [];
+
+    addListener(callback: (arg1: string, arg2: number) => void): void {
+      this.listenerWasAdded = true;
+      this.activeListeners.push(callback);
+    }
+    getRules(callback: (rules: chrome.events.Rule[]) => void): void;
+    getRules(ruleIdentifiers: string[], callback: (rules: chrome.events.Rule[]) => void): void;
+    getRules(ruleIdentifiers: unknown, callback?: unknown): void {
+      throw new Error("Method not implemented.");
+    }
+    hasListener(callback: (arg1: string, arg2: number) => void): boolean {
+      throw new Error("Method not implemented.");
+    }
+    removeRules(ruleIdentifiers?: string[], callback?: () => void): void;
+    removeRules(callback?: () => void): void;
+    removeRules(ruleIdentifiers?: unknown, callback?: unknown): void {
+      throw new Error("Method not implemented.");
+    }
+    addRules(rules: chrome.events.Rule[], callback?: (rules: chrome.events.Rule[]) => void): void {
+      throw new Error("Method not implemented.");
+    }
+    removeListener(callback: (arg1: string, arg2: number) => void): void {
+      const index = this.activeListeners.findIndex((c) => c == callback);
+      if (index === -1) {
+        throw new Error("No registered callback.");
+      }
+
+      this.listenerWasRemoved = true;
+      this.activeListeners.splice(index, 1);
+    }
+    hasListeners(): boolean {
+      throw new Error("Method not implemented.");
+    }
+
+    fireEvent(arg1: string, arg2: number) {
+      this.activeListeners.forEach((listener) => {
+        listener(arg1, arg2);
+      });
+    }
+  }
+
+  let event: FakeEvent;
+
+  beforeEach(() => {
+    event = new FakeEvent();
+  });
+
+  it("should never call addListener when never subscribed to", () => {
+    fromChromeEvent(event);
+    expect(event.listenerWasAdded).toBeFalsy();
+  });
+
+  it("should add a listener when subscribed to.", () => {
+    const eventObservable = fromChromeEvent(event);
+    eventObservable.subscribe();
+    expect(event.listenerWasAdded).toBeTruthy();
+    expect(event.activeListeners).toHaveLength(1);
+  });
+
+  it("should call remove listener when the created subscription is unsubscribed", () => {
+    const eventObservable = fromChromeEvent(event);
+    const subscription = eventObservable.subscribe();
+    subscription.unsubscribe();
+    expect(event.listenerWasAdded).toBeTruthy();
+    expect(event.listenerWasRemoved).toBeTruthy();
+    expect(event.activeListeners).toHaveLength(0);
+  });
+
+  it("should fire each callback given to subscribe", () => {
+    const eventObservable = fromChromeEvent(event);
+
+    let subscription1Called = false;
+    let subscription2Called = false;
+
+    const subscription1 = eventObservable.subscribe(([arg1, arg2]) => {
+      expect(arg1).toBe("Hi!");
+      expect(arg2).toBe(2);
+      subscription1Called = true;
+    });
+
+    const subscription2 = eventObservable.subscribe(([arg1, arg2]) => {
+      expect(arg1).toBe("Hi!");
+      expect(arg2).toBe(2);
+      subscription2Called = true;
+    });
+
+    event.fireEvent("Hi!", 2);
+
+    subscription1.unsubscribe();
+    subscription2.unsubscribe();
+
+    expect(event.activeListeners).toHaveLength(0);
+    expect(subscription1Called).toBeTruthy();
+    expect(subscription2Called).toBeTruthy();
+  });
+});

apps/browser/src/platform/browser/from-chrome-event.ts

@@ -0,0 +1,39 @@
+import { Observable } from "rxjs";
+
+import { BrowserApi } from "./browser-api";
+
+/**
+ * Converts a Chrome event to an Observable stream.
+ *
+ * @typeParam T - The type of the event arguments.
+ * @param event - The Chrome event to convert.
+ * @returns An Observable stream of the event arguments.
+ *
+ * @remarks
+ * This function creates an Observable stream that listens to a Chrome event and emits its arguments
+ * whenever the event is triggered. If the event throws an error, the Observable will emit an error
+ * notification with the error message.
+ *
+ * @example
+ * ```typescript
+ * const onMessage = fromChromeEvent(chrome.runtime.onMessage);
+ * onMessage.subscribe((message) => console.log('Received message:', message));
+ * ```
+ */
+export function fromChromeEvent<T extends unknown[]>(
+  event: chrome.events.Event<(...args: T) => void>
+): Observable<T> {
+  return new Observable<T>((subscriber) => {
+    const handler = (...args: T) => {
+      if (chrome.runtime.lastError) {
+        subscriber.error(chrome.runtime.lastError);
+        return;
+      }
+
+      subscriber.next(args);
+    };
+
+    BrowserApi.addListener(event, handler);
+    return () => BrowserApi.removeListener(event, handler);
+  });
+}

apps/browser/src/platform/services/abstractions/abstract-chrome-storage-api.service.ts

@@ -1,7 +1,39 @@
-import { AbstractStorageService } from "@bitwarden/common/platform/abstractions/storage.service";
+import { Observable, mergeMap } from "rxjs";
+
+import {
+  AbstractStorageService,
+  StorageUpdate,
+  StorageUpdateType,
+} from "@bitwarden/common/platform/abstractions/storage.service";
+
+import { fromChromeEvent } from "../../browser/from-chrome-event";
 
 export default abstract class AbstractChromeStorageService implements AbstractStorageService {
-  protected abstract chromeStorageApi: chrome.storage.StorageArea;
+  constructor(protected chromeStorageApi: chrome.storage.StorageArea) {}
+
+  get updates$(): Observable<StorageUpdate> {
+    return fromChromeEvent(this.chromeStorageApi.onChanged).pipe(
+      mergeMap(([changes]) => {
+        return Object.entries(changes).map(([key, change]) => {
+          // The `newValue` property isn't on the StorageChange object
+          // when the change was from a remove. Similarly a check of the `oldValue`
+          // could be used to tell if the operation was the first creation of this key
+          // but we currently do not differentiate that.
+          // Ref: https://developer.chrome.com/docs/extensions/reference/storage/#type-StorageChange
+          // Ref: https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/API/storage/StorageChange
+          const updateType: StorageUpdateType = "newValue" in change ? "save" : "remove";
+
+          return {
+            key: key,
+            // For removes this property will not exist but then it will just be
+            // undefined which is fine.
+            value: change.newValue,
+            updateType: updateType,
+          };
+        });
+      })
+    );
+  }
 
   async get<T>(key: string): Promise<T> {
     return new Promise((resolve) => {
@@ -22,11 +54,7 @@ export default abstract class AbstractChromeStorageService implements AbstractSt
   async save(key: string, obj: any): Promise<void> {
     if (obj == null) {
       // Fix safari not liking null in set
-      return new Promise<void>((resolve) => {
-        this.chromeStorageApi.remove(key, () => {
-          resolve();
-        });
-      });
+      return this.remove(key);
     }
 
     if (obj instanceof Set) {

apps/browser/src/platform/services/browser-local-storage.service.ts

@@ -1,5 +1,7 @@
 import AbstractChromeStorageService from "./abstractions/abstract-chrome-storage-api.service";
 
 export default class BrowserLocalStorageService extends AbstractChromeStorageService {
-  protected chromeStorageApi = chrome.storage.local;
+  constructor() {
+    super(chrome.storage.local);
+  }
 }

apps/browser/src/platform/services/browser-memory-storage.service.ts

@@ -1,5 +1,7 @@
 import AbstractChromeStorageService from "./abstractions/abstract-chrome-storage-api.service";
 
 export default class BrowserMemoryStorageService extends AbstractChromeStorageService {
-  protected chromeStorageApi = chrome.storage.session;
+  constructor() {
+    super(chrome.storage.session);
+  }
 }

apps/browser/src/platform/services/local-backed-session-storage.service.ts

@@ -1,7 +1,11 @@
+import { Subject } from "rxjs";
 import { Jsonify } from "type-fest";
 
 import { EncryptService } from "@bitwarden/common/platform/abstractions/encrypt.service";
-import { AbstractMemoryStorageService } from "@bitwarden/common/platform/abstractions/storage.service";
+import {
+  AbstractMemoryStorageService,
+  StorageUpdate,
+} from "@bitwarden/common/platform/abstractions/storage.service";
 import { EncString } from "@bitwarden/common/platform/models/domain/enc-string";
 import { MemoryStorageOptions } from "@bitwarden/common/platform/models/domain/storage-options";
 import { SymmetricCryptoKey } from "@bitwarden/common/platform/models/domain/symmetric-crypto-key";
@@ -22,6 +26,7 @@ export class LocalBackedSessionStorageService extends AbstractMemoryStorageServi
   private cache = new Map<string, unknown>();
   private localStorage = new BrowserLocalStorageService();
   private sessionStorage = new BrowserMemoryStorageService();
+  private updatesSubject = new Subject<StorageUpdate>();
 
   constructor(
     private encryptService: EncryptService,
@@ -30,6 +35,10 @@ export class LocalBackedSessionStorageService extends AbstractMemoryStorageServi
     super();
   }
 
+  get updates$() {
+    return this.updatesSubject.asObservable();
+  }
+
   async get<T>(key: string, options?: MemoryStorageOptions<T>): Promise<T> {
     if (this.cache.has(key)) {
       return this.cache.get(key) as T;

apps/browser/src/vault/fido2/browser-fido2-user-interface.service.ts

@@ -219,6 +219,9 @@ export class BrowserFido2UserInterfaceSession implements Fido2UserInterfaceSessi
       });
 
     this.windowClosed$ = fromEventPattern(
+      // FIXME: Make sure that is does not cause a memory leak in Safari or use BrowserApi.AddListener
+      // and test that it doesn't break. Tracking Ticket: https://bitwarden.atlassian.net/browse/PM-4735
+      // eslint-disable-next-line no-restricted-syntax
       (handler: any) => chrome.windows.onRemoved.addListener(handler),
       (handler: any) => chrome.windows.onRemoved.removeListener(handler)
     );

apps/cli/src/platform/services/lowdb-storage.service.ts

@@ -5,10 +5,14 @@ import * as lowdb from "lowdb";
 import * as FileSync from "lowdb/adapters/FileSync";
 import * as lock from "proper-lockfile";
 import { OperationOptions } from "retry";
+import { Subject } from "rxjs";
 
 import { NodeUtils } from "@bitwarden/common/misc/nodeUtils";
 import { LogService } from "@bitwarden/common/platform/abstractions/log.service";
-import { AbstractStorageService } from "@bitwarden/common/platform/abstractions/storage.service";
+import {
+  AbstractStorageService,
+  StorageUpdate,
+} from "@bitwarden/common/platform/abstractions/storage.service";
 import { sequentialize } from "@bitwarden/common/platform/misc/sequentialize";
 import { Utils } from "@bitwarden/common/platform/misc/utils";
 
@@ -24,6 +28,7 @@ export class LowdbStorageService implements AbstractStorageService {
   private db: lowdb.LowdbSync<any>;
   private defaults: any;
   private ready = false;
+  private updatesSubject = new Subject<StorageUpdate>();
 
   constructor(
     protected logService: LogService,
@@ -102,6 +107,10 @@ export class LowdbStorageService implements AbstractStorageService {
     this.ready = true;
   }
 
+  get updates$() {
+    return this.updatesSubject.asObservable();
+  }
+
   async get<T>(key: string): Promise<T> {
     await this.waitForReady();
     return this.lockDbFile(() => {
@@ -119,21 +128,23 @@ export class LowdbStorageService implements AbstractStorageService {
     return this.get(key).then((v) => v != null);
   }
 
-  async save(key: string, obj: any): Promise<any> {
+  async save(key: string, obj: any): Promise<void> {
     await this.waitForReady();
     return this.lockDbFile(() => {
       this.readForNoCache();
       this.db.set(key, obj).write();
+      this.updatesSubject.next({ key, value: obj, updateType: "save" });
       this.logService.debug(`Successfully wrote ${key} to db`);
       return;
     });
   }
 
-  async remove(key: string): Promise<any> {
+  async remove(key: string): Promise<void> {
     await this.waitForReady();
     return this.lockDbFile(() => {
       this.readForNoCache();
       this.db.unset(key).write();
+      this.updatesSubject.next({ key, value: null, updateType: "remove" });
       this.logService.debug(`Successfully removed ${key} from db`);
       return;
     });

apps/cli/src/platform/services/node-env-secure-storage.service.ts

@@ -1,3 +1,5 @@
+import { throwError } from "rxjs";
+
 import { CryptoService } from "@bitwarden/common/platform/abstractions/crypto.service";
 import { LogService } from "@bitwarden/common/platform/abstractions/log.service";
 import { AbstractStorageService } from "@bitwarden/common/platform/abstractions/storage.service";
@@ -12,6 +14,12 @@ export class NodeEnvSecureStorageService implements AbstractStorageService {
     private cryptoService: () => CryptoService
   ) {}
 
+  get updates$() {
+    return throwError(
+      () => new Error("Secure storage implementations cannot have their updates subscribed to.")
+    );
+  }
+
   async get<T>(key: string): Promise<T> {
     const value = await this.storageService.get<string>(this.makeProtectedStorageKey(key));
     if (value == null) {
@@ -25,7 +33,7 @@ export class NodeEnvSecureStorageService implements AbstractStorageService {
     return (await this.get(key)) != null;
   }
 
-  async save(key: string, obj: any): Promise<any> {
+  async save(key: string, obj: any): Promise<void> {
     if (obj == null) {
       return this.remove(key);
     }
@@ -37,8 +45,9 @@ export class NodeEnvSecureStorageService implements AbstractStorageService {
     await this.storageService.save(this.makeProtectedStorageKey(key), protectedObj);
   }
 
-  remove(key: string): Promise<any> {
-    return this.storageService.remove(this.makeProtectedStorageKey(key));
+  async remove(key: string): Promise<void> {
+    await this.storageService.remove(this.makeProtectedStorageKey(key));
+    return;
   }
 
   private async encrypt(plainValue: string): Promise<string> {

apps/desktop/src/platform/services/electron-renderer-secure-storage.service.ts

@@ -1,7 +1,15 @@
+import { throwError } from "rxjs";
+
 import { AbstractStorageService } from "@bitwarden/common/platform/abstractions/storage.service";
 import { StorageOptions } from "@bitwarden/common/platform/models/domain/storage-options";
 
 export class ElectronRendererSecureStorageService implements AbstractStorageService {
+  get updates$() {
+    return throwError(
+      () => new Error("Secure storage implementations cannot have their updates subscribed to.")
+    );
+  }
+
   async get<T>(key: string, options?: StorageOptions): Promise<T> {
     const val = await ipc.platform.passwords.get(key, options?.keySuffix ?? "");
     return val != null ? (JSON.parse(val) as T) : null;
@@ -12,11 +20,11 @@ export class ElectronRendererSecureStorageService implements AbstractStorageServ
     return !!val;
   }
 
-  async save(key: string, obj: any, options?: StorageOptions): Promise<any> {
+  async save<T>(key: string, obj: T, options?: StorageOptions): Promise<void> {
     await ipc.platform.passwords.set(key, options?.keySuffix ?? "", JSON.stringify(obj));
   }
 
-  async remove(key: string, options?: StorageOptions): Promise<any> {
+  async remove(key: string, options?: StorageOptions): Promise<void> {
     await ipc.platform.passwords.delete(key, options?.keySuffix ?? "");
   }
 }

apps/desktop/src/platform/services/electron-renderer-storage.service.ts

@@ -1,6 +1,17 @@
-import { AbstractStorageService } from "@bitwarden/common/platform/abstractions/storage.service";
+import { Subject } from "rxjs";
+
+import {
+  AbstractStorageService,
+  StorageUpdate,
+} from "@bitwarden/common/platform/abstractions/storage.service";
 
 export class ElectronRendererStorageService implements AbstractStorageService {
+  private updatesSubject = new Subject<StorageUpdate>();
+
+  get updates$() {
+    return this.updatesSubject.asObservable();
+  }
+
   get<T>(key: string): Promise<T> {
     return ipc.platform.storage.get(key);
   }
@@ -9,11 +20,13 @@ export class ElectronRendererStorageService implements AbstractStorageService {
     return ipc.platform.storage.has(key);
   }
 
-  save(key: string, obj: any): Promise<any> {
-    return ipc.platform.storage.save(key, obj);
+  async save<T>(key: string, obj: T): Promise<void> {
+    await ipc.platform.storage.save(key, obj);
+    this.updatesSubject.next({ key, value: obj, updateType: "save" });
   }
 
-  remove(key: string): Promise<any> {
-    return ipc.platform.storage.remove(key);
+  async remove(key: string): Promise<void> {
+    await ipc.platform.storage.remove(key);
+    this.updatesSubject.next({ key, value: null, updateType: "remove" });
   }
 }

apps/desktop/src/platform/services/electron-storage.service.ts

@@ -1,9 +1,13 @@
 import * as fs from "fs";
 
 import { ipcMain } from "electron";
+import { Subject } from "rxjs";
 
 import { NodeUtils } from "@bitwarden/common/misc/nodeUtils";
-import { AbstractStorageService } from "@bitwarden/common/platform/abstractions/storage.service";
+import {
+  AbstractStorageService,
+  StorageUpdate,
+} from "@bitwarden/common/platform/abstractions/storage.service";
 
 // See: https://github.com/sindresorhus/electron-store/blob/main/index.d.ts
 interface ElectronStoreOptions {
@@ -35,6 +39,7 @@ type Options = BaseOptions<"get"> | BaseOptions<"has"> | SaveOptions | BaseOptio
 
 export class ElectronStorageService implements AbstractStorageService {
   private store: ElectronStore;
+  private updatesSubject = new Subject<StorageUpdate>();
 
   constructor(dir: string, defaults = {}) {
     if (!fs.existsSync(dir)) {
@@ -60,6 +65,10 @@ export class ElectronStorageService implements AbstractStorageService {
     });
   }
 
+  get updates$() {
+    return this.updatesSubject.asObservable();
+  }
+
   get<T>(key: string): Promise<T> {
     const val = this.store.get(key) as T;
     return Promise.resolve(val != null ? val : null);
@@ -75,11 +84,13 @@ export class ElectronStorageService implements AbstractStorageService {
       obj = Array.from(obj);
     }
     this.store.set(key, obj);
+    this.updatesSubject.next({ key, value: obj, updateType: "save" });
     return Promise.resolve();
   }
 
   remove(key: string): Promise<void> {
     this.store.delete(key);
+    this.updatesSubject.next({ key, value: null, updateType: "remove" });
     return Promise.resolve();
   }
 }

apps/web/src/app/core/html-storage.service.ts

@@ -1,15 +1,25 @@
 import { Injectable } from "@angular/core";
+import { Subject } from "rxjs";
 
 import { HtmlStorageLocation } from "@bitwarden/common/enums";
-import { AbstractStorageService } from "@bitwarden/common/platform/abstractions/storage.service";
+import {
+  AbstractStorageService,
+  StorageUpdate,
+} from "@bitwarden/common/platform/abstractions/storage.service";
 import { StorageOptions } from "@bitwarden/common/platform/models/domain/storage-options";
 
 @Injectable()
 export class HtmlStorageService implements AbstractStorageService {
+  private updatesSubject = new Subject<StorageUpdate>();
+
   get defaultOptions(): StorageOptions {
     return { htmlStorageLocation: HtmlStorageLocation.Session };
   }
 
+  get updates$() {
+    return this.updatesSubject.asObservable();
+  }
+
   get<T>(key: string, options: StorageOptions = this.defaultOptions): Promise<T> {
     let json: string = null;
     switch (options.htmlStorageLocation) {
@@ -52,6 +62,7 @@ export class HtmlStorageService implements AbstractStorageService {
         window.sessionStorage.setItem(key, json);
         break;
     }
+    this.updatesSubject.next({ key, value: obj, updateType: "save" });
     return Promise.resolve();
   }
 
@@ -65,6 +76,7 @@ export class HtmlStorageService implements AbstractStorageService {
         window.sessionStorage.removeItem(key);
         break;
     }
+    this.updatesSubject.next({ key, value: null, updateType: "remove" });
     return Promise.resolve();
   }
 }

libs/common/spec/fake-storage.service.ts

@@ -0,0 +1,60 @@
+import { MockProxy, mock } from "jest-mock-extended";
+import { Subject } from "rxjs";
+
+import {
+  AbstractStorageService,
+  StorageUpdate,
+} from "../src/platform/abstractions/storage.service";
+import { StorageOptions } from "../src/platform/models/domain/storage-options";
+
+export class FakeStorageService implements AbstractStorageService {
+  private store: Record<string, unknown>;
+  private updatesSubject = new Subject<StorageUpdate>();
+
+  /**
+   * Returns a mock of a {@see AbstractStorageService} for asserting the expected
+   * amount of calls. It is not recommended to use this to mock implementations as
+   * they are not respected.
+   */
+  mock: MockProxy<AbstractStorageService>;
+
+  constructor(initial?: Record<string, unknown>) {
+    this.store = initial ?? {};
+    this.mock = mock<AbstractStorageService>();
+  }
+
+  /**
+   * Updates the internal store for this fake implementation, this bypasses any mock calls
+   * or updates to the {@link updates$} observable.
+   * @param store
+   */
+  internalUpdateStore(store: Record<string, unknown>) {
+    this.store = store;
+  }
+
+  get updates$() {
+    return this.updatesSubject.asObservable();
+  }
+
+  get<T>(key: string, options?: StorageOptions): Promise<T> {
+    this.mock.get(key, options);
+    const value = this.store[key] as T;
+    return Promise.resolve(value);
+  }
+  has(key: string, options?: StorageOptions): Promise<boolean> {
+    this.mock.has(key, options);
+    return Promise.resolve(this.store[key] != null);
+  }
+  save<T>(key: string, obj: T, options?: StorageOptions): Promise<void> {
+    this.mock.save(key, options);
+    this.store[key] = obj;
+    this.updatesSubject.next({ key: key, value: obj, updateType: "save" });
+    return Promise.resolve();
+  }
+  remove(key: string, options?: StorageOptions): Promise<void> {
+    this.mock.remove(key, options);
+    delete this.store[key];
+    this.updatesSubject.next({ key: key, value: undefined, updateType: "remove" });
+    return Promise.resolve();
+  }
+}

libs/common/spec/utils.ts

@@ -69,12 +69,18 @@ export function trackEmissions<T>(observable: Observable<T>): T[] {
       case "boolean":
         emissions.push(value);
         break;
-      case "object":
-        emissions.push({ ...value });
-        break;
-      default:
-        emissions.push(JSON.parse(JSON.stringify(value)));
+      default: {
+        emissions.push(clone(value));
+      }
     }
   });
   return emissions;
 }
+
+function clone(value: any): any {
+  if (global.structuredClone != undefined) {
+    return structuredClone(value);
+  } else {
+    return JSON.parse(JSON.stringify(value));
+  }
+}

libs/common/src/platform/abstractions/storage.service.ts

@@ -1,6 +1,21 @@
+import { Observable } from "rxjs";
+
 import { MemoryStorageOptions, StorageOptions } from "../models/domain/storage-options";
 
+export type StorageUpdateType = "save" | "remove";
+export type StorageUpdate = {
+  key: string;
+  value?: unknown;
+  updateType: StorageUpdateType;
+};
+
 export abstract class AbstractStorageService {
+  /**
+   * Provides an {@link Observable} that represents a stream of updates that
+   * have happened in this storage service or in the storage this service provides
+   * an interface to.
+   */
+  abstract get updates$(): Observable<StorageUpdate>;
   abstract get<T>(key: string, options?: StorageOptions): Promise<T>;
   abstract has(key: string, options?: StorageOptions): Promise<boolean>;
   abstract save<T>(key: string, obj: T, options?: StorageOptions): Promise<void>;

libs/common/src/platform/services/memory-storage.service.ts

@@ -1,7 +1,14 @@
-import { AbstractMemoryStorageService } from "../abstractions/storage.service";
+import { Subject } from "rxjs";
+
+import { AbstractMemoryStorageService, StorageUpdate } from "../abstractions/storage.service";
 
 export class MemoryStorageService extends AbstractMemoryStorageService {
-  private store = new Map<string, any>();
+  private store = new Map<string, unknown>();
+  private updatesSubject = new Subject<StorageUpdate>();
+
+  get updates$() {
+    return this.updatesSubject.asObservable();
+  }
 
   get<T>(key: string): Promise<T> {
     if (this.store.has(key)) {
@@ -15,16 +22,18 @@ export class MemoryStorageService extends AbstractMemoryStorageService {
     return (await this.get(key)) != null;
   }
 
-  save(key: string, obj: any): Promise<any> {
+  save<T>(key: string, obj: T): Promise<void> {
     if (obj == null) {
       return this.remove(key);
     }
     this.store.set(key, obj);
+    this.updatesSubject.next({ key, value: obj, updateType: "save" });
     return Promise.resolve();
   }
 
-  remove(key: string): Promise<any> {
+  remove(key: string): Promise<void> {
     this.store.delete(key);
+    this.updatesSubject.next({ key, value: null, updateType: "remove" });
     return Promise.resolve();
   }
 

libs/common/src/platform/state/derived-user-state.ts

@@ -0,0 +1,5 @@
+import { Observable } from "rxjs";
+
+export interface DerivedUserState<T> {
+  state$: Observable<T>;
+}

libs/common/src/platform/state/global-state.provider.ts

@@ -0,0 +1,13 @@
+import { GlobalState } from "./global-state";
+import { KeyDefinition } from "./key-definition";
+
+/**
+ * A provider for geting an implementation of global state scoped to the given key.
+ */
+export abstract class GlobalStateProvider {
+  /**
+   * Gets a {@link GlobalState} scoped to the given {@link KeyDefinition}
+   * @param keyDefinition - The {@link KeyDefinition} for which you want the state for.
+   */
+  get: <T>(keyDefinition: KeyDefinition<T>) => GlobalState<T>;
+}

libs/common/src/platform/state/global-state.ts

@@ -0,0 +1,20 @@
+import { Observable } from "rxjs";
+
+/**
+ * A helper object for interacting with state that is scoped to a specific domain
+ * but is not scoped to a user. This is application wide storage.
+ */
+export interface GlobalState<T> {
+  /**
+   * Method for allowing you to manipulate state in an additive way.
+   * @param configureState callback for how you want manipulate this section of state
+   * @returns A promise that must be awaited before your next action to ensure the update has been written to state.
+   */
+  update: (configureState: (state: T) => T) => Promise<T>;
+
+  /**
+   * An observable stream of this state, the first emission of this will be the current state on disk
+   * and subsequent updates will be from an update to that state.
+   */
+  state$: Observable<T>;
+}

libs/common/src/platform/state/implementations/default-derived-state.ts

@@ -0,0 +1,23 @@
+import { Observable, switchMap } from "rxjs";
+
+import { EncryptService } from "../../abstractions/encrypt.service";
+import { DerivedUserState } from "../derived-user-state";
+import { Converter, DeriveContext, UserState } from "../user-state";
+
+export class DefaultDerivedUserState<TFrom, TTo> implements DerivedUserState<TTo> {
+  state$: Observable<TTo>;
+
+  constructor(
+    private converter: Converter<TFrom, TTo>,
+    private encryptService: EncryptService,
+    private userState: UserState<TFrom>
+  ) {
+    this.state$ = userState.state$.pipe(
+      switchMap(async (from) => {
+        // TODO: How do I get the key?
+        const convertedData = await this.converter(from, new DeriveContext(null, encryptService));
+        return convertedData;
+      })
+    );
+  }
+}

libs/common/src/platform/state/implementations/default-global-state.provider.ts

@@ -0,0 +1,46 @@
+import {
+  AbstractMemoryStorageService,
+  AbstractStorageService,
+} from "../../abstractions/storage.service";
+import { GlobalState } from "../global-state";
+import { GlobalStateProvider } from "../global-state.provider";
+import { KeyDefinition } from "../key-definition";
+import { StorageLocation } from "../state-definition";
+
+import { DefaultGlobalState } from "./default-global-state";
+
+export class DefaultGlobalStateProvider implements GlobalStateProvider {
+  private globalStateCache: Record<string, GlobalState<unknown>> = {};
+
+  constructor(
+    private memoryStorage: AbstractMemoryStorageService,
+    private diskStorage: AbstractStorageService
+  ) {}
+
+  get<T>(keyDefinition: KeyDefinition<T>): GlobalState<T> {
+    const cacheKey = keyDefinition.buildCacheKey();
+    const existingGlobalState = this.globalStateCache[cacheKey];
+    if (existingGlobalState != null) {
+      // The cast into the actual generic is safe because of rules around key definitions
+      // being unique.
+      return existingGlobalState as DefaultGlobalState<T>;
+    }
+
+    const newGlobalState = new DefaultGlobalState<T>(
+      keyDefinition,
+      this.getLocation(keyDefinition.stateDefinition.storageLocation)
+    );
+
+    this.globalStateCache[cacheKey] = newGlobalState;
+    return newGlobalState;
+  }
+
+  private getLocation(location: StorageLocation) {
+    switch (location) {
+      case "disk":
+        return this.diskStorage;
+      case "memory":
+        return this.memoryStorage;
+    }
+  }
+}

libs/common/src/platform/state/implementations/default-global-state.spec.ts

@@ -0,0 +1,98 @@
+/**
+ * need to update test environment so trackEmissions works appropriately
+ * @jest-environment ../shared/test.environment.ts
+ */
+
+import { Jsonify } from "type-fest";
+
+import { trackEmissions } from "../../../../spec";
+import { FakeStorageService } from "../../../../spec/fake-storage.service";
+import { KeyDefinition, globalKeyBuilder } from "../key-definition";
+import { StateDefinition } from "../state-definition";
+
+import { DefaultGlobalState } from "./default-global-state";
+
+class TestState {
+  date: Date;
+
+  static fromJSON(jsonState: Jsonify<TestState>) {
+    if (jsonState == null) {
+      return null;
+    }
+
+    return Object.assign(new TestState(), jsonState, {
+      date: new Date(jsonState.date),
+    });
+  }
+}
+
+const testStateDefinition = new StateDefinition("fake", "disk");
+
+const testKeyDefinition = new KeyDefinition<TestState>(
+  testStateDefinition,
+  "fake",
+  TestState.fromJSON
+);
+const globalKey = globalKeyBuilder(testKeyDefinition);
+
+describe("DefaultGlobalState", () => {
+  let diskStorageService: FakeStorageService;
+  let globalState: DefaultGlobalState<TestState>;
+
+  beforeEach(() => {
+    diskStorageService = new FakeStorageService();
+    globalState = new DefaultGlobalState(testKeyDefinition, diskStorageService);
+  });
+
+  afterEach(() => {
+    jest.resetAllMocks();
+  });
+
+  it("should emit when storage updates", async () => {
+    const emissions = trackEmissions(globalState.state$);
+    const newData = { date: new Date() };
+    await diskStorageService.save(globalKey, newData);
+
+    expect(emissions).toEqual([
+      null, // Initial value
+      newData,
+      // JSON.parse(JSON.stringify(newData)), // This is due to the way `trackEmissions` clones
+    ]);
+  });
+
+  it("should not emit when update key does not match", async () => {
+    const emissions = trackEmissions(globalState.state$);
+    const newData = { date: new Date() };
+    await diskStorageService.save("wrong_key", newData);
+
+    expect(emissions).toEqual(
+      expect.arrayContaining([
+        null, // Initial value
+      ])
+    );
+  });
+
+  it("should save on update", async () => {
+    const newData = { date: new Date() };
+    const result = await globalState.update((state) => {
+      return newData;
+    });
+
+    expect(diskStorageService.mock.save).toHaveBeenCalledTimes(1);
+    expect(result).toEqual(newData);
+  });
+
+  it("should emit once per update", async () => {
+    const emissions = trackEmissions(globalState.state$);
+    const newData = { date: new Date() };
+
+    await globalState.update((state) => {
+      return newData;
+    });
+
+    expect(emissions).toEqual([
+      null, // Initial value
+      newData,
+    ]);
+  });
+});

libs/common/src/platform/state/implementations/default-global-state.ts

@@ -0,0 +1,60 @@
+import { BehaviorSubject, Observable, defer, filter, map, shareReplay, tap } from "rxjs";
+import { Jsonify } from "type-fest";
+
+import { AbstractStorageService } from "../../abstractions/storage.service";
+import { GlobalState } from "../global-state";
+import { KeyDefinition, globalKeyBuilder } from "../key-definition";
+
+export class DefaultGlobalState<T> implements GlobalState<T> {
+  private storageKey: string;
+  private seededPromise: Promise<void>;
+
+  protected stateSubject: BehaviorSubject<T | null> = new BehaviorSubject<T | null>(null);
+
+  state$: Observable<T>;
+
+  constructor(
+    private keyDefinition: KeyDefinition<T>,
+    private chosenLocation: AbstractStorageService
+  ) {
+    this.storageKey = globalKeyBuilder(this.keyDefinition);
+
+    this.seededPromise = this.chosenLocation.get<Jsonify<T>>(this.storageKey).then((data) => {
+      const serializedData = this.keyDefinition.deserializer(data);
+      this.stateSubject.next(serializedData);
+    });
+
+    const storageUpdates$ = this.chosenLocation.updates$.pipe(
+      filter((update) => update.key === this.storageKey),
+      map((update) => {
+        return this.keyDefinition.deserializer(update.value as Jsonify<T>);
+      }),
+      shareReplay({ bufferSize: 1, refCount: false })
+    );
+
+    this.state$ = defer(() => {
+      const storageUpdateSubscription = storageUpdates$.subscribe((value) => {
+        this.stateSubject.next(value);
+      });
+
+      return this.stateSubject.pipe(
+        tap({
+          complete: () => storageUpdateSubscription.unsubscribe(),
+        })
+      );
+    });
+  }
+
+  async update(configureState: (state: T) => T): Promise<T> {
+    await this.seededPromise;
+    const currentState = this.stateSubject.getValue();
+    const newState = configureState(currentState);
+    await this.chosenLocation.save(this.storageKey, newState);
+    return newState;
+  }
+
+  async getFromState(): Promise<T> {
+    const data = await this.chosenLocation.get<Jsonify<T>>(this.storageKey);
+    return this.keyDefinition.deserializer(data);
+  }
+}

libs/common/src/platform/state/implementations/default-user-state.provider.ts

@@ -0,0 +1,55 @@
+import { AccountService } from "../../../auth/abstractions/account.service";
+import { EncryptService } from "../../abstractions/encrypt.service";
+import {
+  AbstractMemoryStorageService,
+  AbstractStorageService,
+} from "../../abstractions/storage.service";
+import { KeyDefinition } from "../key-definition";
+import { StorageLocation } from "../state-definition";
+import { UserState } from "../user-state";
+import { UserStateProvider } from "../user-state.provider";
+
+import { DefaultUserState } from "./default-user-state";
+
+export class DefaultUserStateProvider implements UserStateProvider {
+  private userStateCache: Record<string, UserState<unknown>> = {};
+
+  constructor(
+    protected accountService: AccountService,
+    protected encryptService: EncryptService,
+    protected memoryStorage: AbstractMemoryStorageService,
+    protected diskStorage: AbstractStorageService
+  ) {}
+
+  get<T>(keyDefinition: KeyDefinition<T>): UserState<T> {
+    const cacheKey = keyDefinition.buildCacheKey();
+    const existingUserState = this.userStateCache[cacheKey];
+    if (existingUserState != null) {
+      // I have to cast out of the unknown generic but this should be safe if rules
+      // around domain token are made
+      return existingUserState as DefaultUserState<T>;
+    }
+
+    const newUserState = this.buildUserState(keyDefinition);
+    this.userStateCache[cacheKey] = newUserState;
+    return newUserState;
+  }
+
+  protected buildUserState<T>(keyDefinition: KeyDefinition<T>): UserState<T> {
+    return new DefaultUserState<T>(
+      keyDefinition,
+      this.accountService,
+      this.encryptService,
+      this.getLocation(keyDefinition.stateDefinition.storageLocation)
+    );
+  }
+
+  private getLocation(location: StorageLocation) {
+    switch (location) {
+      case "disk":
+        return this.diskStorage;
+      case "memory":
+        return this.memoryStorage;
+    }
+  }
+}

libs/common/src/platform/state/implementations/default-user-state.spec.ts

@@ -0,0 +1,236 @@
+import { any, mock } from "jest-mock-extended";
+import { BehaviorSubject, firstValueFrom, timeout } from "rxjs";
+import { Jsonify } from "type-fest";
+
+import { trackEmissions } from "../../../../spec";
+import { FakeStorageService } from "../../../../spec/fake-storage.service";
+import { AccountInfo, AccountService } from "../../../auth/abstractions/account.service";
+import { AuthenticationStatus } from "../../../auth/enums/authentication-status";
+import { UserId } from "../../../types/guid";
+import { KeyDefinition } from "../key-definition";
+import { StateDefinition } from "../state-definition";
+
+import { DefaultUserState } from "./default-user-state";
+
+class TestState {
+  date: Date;
+  array: string[];
+
+  static fromJSON(jsonState: Jsonify<TestState>) {
+    if (jsonState == null) {
+      return null;
+    }
+
+    return Object.assign(new TestState(), jsonState, {
+      date: new Date(jsonState.date),
+    });
+  }
+}
+
+const testStateDefinition = new StateDefinition("fake", "disk");
+
+const testKeyDefinition = new KeyDefinition<TestState>(
+  testStateDefinition,
+  "fake",
+  TestState.fromJSON
+);
+
+describe("DefaultUserState", () => {
+  const accountService = mock<AccountService>();
+  let diskStorageService: FakeStorageService;
+  let activeAccountSubject: BehaviorSubject<{ id: UserId } & AccountInfo>;
+  let userState: DefaultUserState<TestState>;
+
+  beforeEach(() => {
+    activeAccountSubject = new BehaviorSubject<{ id: UserId } & AccountInfo>(undefined);
+    accountService.activeAccount$ = activeAccountSubject;
+
+    diskStorageService = new FakeStorageService();
+    userState = new DefaultUserState(
+      testKeyDefinition,
+      accountService,
+      null, // Not testing anything with encrypt service
+      diskStorageService
+    );
+  });
+
+  const changeActiveUser = async (id: string) => {
+    const userId = id != null ? `00000000-0000-1000-a000-00000000000${id}` : undefined;
+    activeAccountSubject.next({
+      id: userId as UserId,
+      email: `test${id}@example.com`,
+      name: `Test User ${id}`,
+      status: AuthenticationStatus.Unlocked,
+    });
+    await new Promise((resolve) => setTimeout(resolve, 1));
+  };
+
+  afterEach(() => {
+    jest.resetAllMocks();
+  });
+
+  it("emits updates for each user switch and update", async () => {
+    diskStorageService.internalUpdateStore({
+      "user_00000000-0000-1000-a000-000000000001_fake_fake": {
+        date: "2022-09-21T13:14:17.648Z",
+        array: ["value1", "value2"],
+      } as Jsonify<TestState>,
+      "user_00000000-0000-1000-a000-000000000002_fake_fake": {
+        date: "2021-09-21T13:14:17.648Z",
+        array: ["user2_value"],
+      },
+    });
+
+    const emissions = trackEmissions(userState.state$);
+
+    // User signs in
+    changeActiveUser("1");
+    await new Promise<void>((resolve) => setTimeout(resolve, 1));
+
+    // Service does an update
+    await userState.update((state) => {
+      state.array.push("value3");
+      state.date = new Date(2023, 0);
+      return state;
+    });
+    await new Promise<void>((resolve) => setTimeout(resolve, 1));
+
+    // Emulate an account switch
+    await changeActiveUser("2");
+
+    expect(emissions).toHaveLength(3);
+    // Gotten starter user data
+    expect(emissions[0]).toBeTruthy();
+    expect(emissions[0].array).toHaveLength(2);
+
+    // Gotten emission for the update call
+    expect(emissions[1]).toBeTruthy();
+    expect(emissions[1].array).toHaveLength(3);
+    expect(new Date(emissions[1].date).getUTCFullYear()).toBe(2023);
+
+    // The second users data
+    expect(emissions[2]).toBeTruthy();
+    expect(emissions[2].array).toHaveLength(1);
+    expect(new Date(emissions[2].date).getUTCFullYear()).toBe(2021);
+
+    // Should only be called twice to get state, once for each user
+    expect(diskStorageService.mock.get).toHaveBeenCalledTimes(2);
+    expect(diskStorageService.mock.get).toHaveBeenNthCalledWith(
+      1,
+      "user_00000000-0000-1000-a000-000000000001_fake_fake",
+      any()
+    );
+    expect(diskStorageService.mock.get).toHaveBeenNthCalledWith(
+      2,
+      "user_00000000-0000-1000-a000-000000000002_fake_fake",
+      any()
+    );
+
+    // Should only have saved data for the first user
+    expect(diskStorageService.mock.save).toHaveBeenCalledTimes(1);
+    expect(diskStorageService.mock.save).toHaveBeenNthCalledWith(
+      1,
+      "user_00000000-0000-1000-a000-000000000001_fake_fake",
+      any()
+    );
+  });
+
+  it("will not emit any value if there isn't an active user", async () => {
+    let resolvedValue: TestState | undefined = undefined;
+    let rejectedError: Error | undefined = undefined;
+
+    const promise = firstValueFrom(userState.state$.pipe(timeout(20)))
+      .then((value) => {
+        resolvedValue = value;
+      })
+      .catch((err) => {
+        rejectedError = err;
+      });
+    await promise;
+
+    expect(diskStorageService.mock.get).not.toHaveBeenCalled();
+
+    expect(resolvedValue).toBe(undefined);
+    expect(rejectedError).toBeTruthy();
+    expect(rejectedError.message).toBe("Timeout has occurred");
+  });
+
+  it("will emit value for a new active user after subscription started", async () => {
+    let resolvedValue: TestState | undefined = undefined;
+    let rejectedError: Error | undefined = undefined;
+
+    diskStorageService.internalUpdateStore({
+      "user_00000000-0000-1000-a000-000000000001_fake_fake": {
+        date: "2020-09-21T13:14:17.648Z",
+        array: ["testValue"],
+      } as Jsonify<TestState>,
+    });
+
+    const promise = firstValueFrom(userState.state$.pipe(timeout(20)))
+      .then((value) => {
+        resolvedValue = value;
+      })
+      .catch((err) => {
+        rejectedError = err;
+      });
+    await changeActiveUser("1");
+    await promise;
+
+    expect(diskStorageService.mock.get).toHaveBeenCalledTimes(1);
+
+    expect(resolvedValue).toBeTruthy();
+    expect(resolvedValue.array).toHaveLength(1);
+    expect(resolvedValue.date.getUTCFullYear()).toBe(2020);
+    expect(rejectedError).toBeFalsy();
+  });
+
+  it("should not emit a previous users value if that user is no longer active", async () => {
+    diskStorageService.internalUpdateStore({
+      "user_00000000-0000-1000-a000-000000000001_fake_fake": {
+        date: "2020-09-21T13:14:17.648Z",
+        array: ["value"],
+      } as Jsonify<TestState>,
+      "user_00000000-0000-1000-a000-000000000002_fake_fake": {
+        date: "2020-09-21T13:14:17.648Z",
+        array: [],
+      } as Jsonify<TestState>,
+    });
+
+    // This starts one subscription on the observable for tracking emissions throughout
+    // the whole test.
+    const emissions = trackEmissions(userState.state$);
+
+    // Change to a user with data
+    await changeActiveUser("1");
+
+    // This should always return a value right await
+    const value = await firstValueFrom(userState.state$);
+    expect(value).toBeTruthy();
+
+    // Make it such that there is no active user
+    await changeActiveUser(undefined);
+
+    let resolvedValue: TestState | undefined = undefined;
+    let rejectedError: Error | undefined = undefined;
+
+    // Even if the observable has previously emitted a value it shouldn't have
+    // a value for the user subscribing to it because there isn't an active user
+    // to get data for.
+    await firstValueFrom(userState.state$.pipe(timeout(20)))
+      .then((value) => {
+        resolvedValue = value;
+      })
+      .catch((err) => {
+        rejectedError = err;
+      });
+
+    expect(resolvedValue).toBeFalsy();
+    expect(rejectedError).toBeTruthy();
+    expect(rejectedError.message).toBe("Timeout has occurred");
+
+    // We need to figure out if something should be emitted
+    // when there becomes no active user, if we don't want that to emit
+    // this value is correct.
+    expect(emissions).toHaveLength(2);
+  });
+});

libs/common/src/platform/state/implementations/default-user-state.ts

@@ -0,0 +1,152 @@
+import {
+  Observable,
+  BehaviorSubject,
+  map,
+  shareReplay,
+  switchMap,
+  tap,
+  defer,
+  firstValueFrom,
+  combineLatestWith,
+  filter,
+} from "rxjs";
+import { Jsonify } from "type-fest";
+
+import { AccountService } from "../../../auth/abstractions/account.service";
+import { UserId } from "../../../types/guid";
+import { EncryptService } from "../../abstractions/encrypt.service";
+import { AbstractStorageService } from "../../abstractions/storage.service";
+import { DerivedUserState } from "../derived-user-state";
+import { KeyDefinition, userKeyBuilder } from "../key-definition";
+import { Converter, UserState } from "../user-state";
+
+import { DefaultDerivedUserState } from "./default-derived-state";
+
+const FAKE_DEFAULT = Symbol("fakeDefault");
+
+export class DefaultUserState<T> implements UserState<T> {
+  private formattedKey$: Observable<string>;
+
+  protected stateSubject: BehaviorSubject<T | typeof FAKE_DEFAULT> = new BehaviorSubject<
+    T | typeof FAKE_DEFAULT
+  >(FAKE_DEFAULT);
+  private stateSubject$ = this.stateSubject.asObservable();
+
+  state$: Observable<T>;
+
+  constructor(
+    protected keyDefinition: KeyDefinition<T>,
+    private accountService: AccountService,
+    private encryptService: EncryptService,
+    private chosenStorageLocation: AbstractStorageService
+  ) {
+    this.formattedKey$ = this.accountService.activeAccount$.pipe(
+      map((account) =>
+        account != null && account.id != null
+          ? userKeyBuilder(account.id, this.keyDefinition)
+          : null
+      ),
+      shareReplay({ bufferSize: 1, refCount: false })
+    );
+
+    const activeAccountData$ = this.formattedKey$.pipe(
+      switchMap(async (key) => {
+        if (key == null) {
+          return FAKE_DEFAULT;
+        }
+        const jsonData = await this.chosenStorageLocation.get<Jsonify<T>>(key);
+        const data = keyDefinition.deserializer(jsonData);
+        return data;
+      }),
+      // Share the execution
+      shareReplay({ refCount: false, bufferSize: 1 })
+    );
+
+    const storageUpdates$ = this.chosenStorageLocation.updates$.pipe(
+      combineLatestWith(this.formattedKey$),
+      filter(([update, key]) => key !== null && update.key === key),
+      map(([update]) => {
+        return keyDefinition.deserializer(update.value as Jsonify<T>);
+      })
+    );
+
+    // Whomever subscribes to this data, should be notified of updated data
+    // if someone calls my update() method, or the active user changes.
+    this.state$ = defer(() => {
+      const accountChangeSubscription = activeAccountData$.subscribe((data) => {
+        this.stateSubject.next(data);
+      });
+      const storageUpdateSubscription = storageUpdates$.subscribe((data) => {
+        this.stateSubject.next(data);
+      });
+
+      return this.stateSubject$.pipe(
+        tap({
+          complete: () => {
+            accountChangeSubscription.unsubscribe();
+            storageUpdateSubscription.unsubscribe();
+          },
+        })
+      );
+    })
+      // I fake the generic here because I am filtering out the other union type
+      // and this makes it so that typescript understands the true type
+      .pipe(filter<T>((value) => value != FAKE_DEFAULT));
+  }
+
+  async update(configureState: (state: T) => T): Promise<T> {
+    const key = await this.createKey();
+    const currentState = await this.getGuaranteedState(key);
+    const newState = configureState(currentState);
+    await this.saveToStorage(key, newState);
+    return newState;
+  }
+
+  async updateFor(userId: UserId, configureState: (state: T) => T): Promise<T> {
+    if (userId == null) {
+      throw new Error("Attempting to update user state, but no userId has been supplied.");
+    }
+
+    const key = userKeyBuilder(userId, this.keyDefinition);
+    const currentStore = await this.chosenStorageLocation.get<Jsonify<T>>(key);
+    const currentState = this.keyDefinition.deserializer(currentStore);
+    const newState = configureState(currentState);
+    await this.saveToStorage(key, newState);
+
+    return newState;
+  }
+
+  async getFromState(): Promise<T> {
+    const key = await this.createKey();
+    const data = await this.chosenStorageLocation.get<Jsonify<T>>(key);
+    return this.keyDefinition.deserializer(data);
+  }
+
+  createDerived<TTo>(converter: Converter<T, TTo>): DerivedUserState<TTo> {
+    return new DefaultDerivedUserState<T, TTo>(converter, this.encryptService, this);
+  }
+
+  protected async createKey(): Promise<string> {
+    const formattedKey = await firstValueFrom(this.formattedKey$);
+    if (formattedKey == null) {
+      throw new Error("Cannot create a key while there is no active user.");
+    }
+    return formattedKey;
+  }
+
+  protected async getGuaranteedState(key: string) {
+    const currentValue = this.stateSubject.getValue();
+    return currentValue === FAKE_DEFAULT ? await this.seedInitial(key) : currentValue;
+  }
+
+  private async seedInitial(key: string): Promise<T> {
+    const data = await this.chosenStorageLocation.get<Jsonify<T>>(key);
+    const serializedData = this.keyDefinition.deserializer(data);
+    this.stateSubject.next(serializedData);
+    return serializedData;
+  }
+
+  protected saveToStorage(key: string, data: T): Promise<void> {
+    return this.chosenStorageLocation.save(key, data);
+  }
+}

libs/common/src/platform/state/index.ts

@@ -0,0 +1,3 @@
+export { DerivedUserState } from "./derived-user-state";
+export { DefaultGlobalStateProvider } from "./implementations/default-global-state.provider";
+export { DefaultUserStateProvider } from "./implementations/default-user-state.provider";

libs/common/src/platform/state/key-definition.ts

@@ -0,0 +1,102 @@
+import { Jsonify, Opaque } from "type-fest";
+
+import { UserId } from "../../types/guid";
+import { Utils } from "../misc/utils";
+
+import { StateDefinition } from "./state-definition";
+
+/**
+ * KeyDefinitions describe the precise location to store data for a given piece of state.
+ * The StateDefinition is used to describe the domain of the state, and the KeyDefinition
+ * sub-divides that domain into specific keys.
+ */
+export class KeyDefinition<T> {
+  /**
+   * Creates a new instance of a KeyDefinition
+   * @param stateDefinition The state definition for which this key belongs to.
+   * @param key The name of the key, this should be unique per domain
+   * @param deserializer A function to use to safely convert your type from json to your expected type.
+   */
+  constructor(
+    readonly stateDefinition: StateDefinition,
+    readonly key: string,
+    readonly deserializer: (jsonValue: Jsonify<T>) => T
+  ) {}
+
+  /**
+   * Creates a {@link KeyDefinition} for state that is an array.
+   * @param stateDefinition The state definition to be added to the KeyDefinition
+   * @param key The key to be added to the KeyDefinition
+   * @param deserializer The deserializer for the element of the array in your state.
+   * @returns A {@link KeyDefinition} that contains a serializer that will run the provided deserializer for each
+   * element of an array **unless that array is null in which case it will return an empty list.**
+   */
+  static array<T>(
+    stateDefinition: StateDefinition,
+    key: string,
+    deserializer: (jsonValue: Jsonify<T>) => T
+  ) {
+    return new KeyDefinition<T[]>(stateDefinition, key, (jsonValue) => {
+      return jsonValue?.map((v) => deserializer(v)) ?? [];
+    });
+  }
+
+  /**
+   * Creates a {@link KeyDefinition} for state that is a record.
+   * @param stateDefinition The state definition to be added to the KeyDefinition
+   * @param key The key to be added to the KeyDefinition
+   * @param deserializer The deserializer for the value part of a record.
+   * @returns A {@link KeyDefinition} that contains a serializer that will run the provided deserializer for each
+   * value in a record and returns every key as a string **unless that record is null in which case it will return an record.**
+   */
+  static record<T>(
+    stateDefinition: StateDefinition,
+    key: string,
+    deserializer: (jsonValue: Jsonify<T>) => T
+  ) {
+    return new KeyDefinition<Record<string, T>>(stateDefinition, key, (jsonValue) => {
+      const output: Record<string, T> = {};
+
+      if (jsonValue == null) {
+        return output;
+      }
+
+      for (const key in jsonValue) {
+        output[key] = deserializer((jsonValue as Record<string, Jsonify<T>>)[key]);
+      }
+      return output;
+    });
+  }
+
+  /**
+   *
+   * @returns
+   */
+  buildCacheKey(): string {
+    return `${this.stateDefinition.storageLocation}_${this.stateDefinition.name}_${this.key}`;
+  }
+}
+
+export type StorageKey = Opaque<string, "StorageKey">;
+
+/**
+ * Creates a {@link StorageKey} that points to the data at the given key definition for the specified user.
+ * @param userId The userId of the user you want the key to be for.
+ * @param keyDefinition The key definition of which data the key should point to.
+ * @returns A key that is ready to be used in a storage service to get data.
+ */
+export function userKeyBuilder(userId: UserId, keyDefinition: KeyDefinition<unknown>): StorageKey {
+  if (!Utils.isGuid(userId)) {
+    throw new Error("You cannot build a user key without a valid UserId");
+  }
+  return `user_${userId}_${keyDefinition.stateDefinition.name}_${keyDefinition.key}` as StorageKey;
+}
+
+/**
+ * Creates a {@link StorageKey}
+ * @param keyDefinition The key definition of which data the key should point to.
+ * @returns A key that is ready to be used in a storage service to get data.
+ */
+export function globalKeyBuilder(keyDefinition: KeyDefinition<unknown>): StorageKey {
+  return `global_${keyDefinition.stateDefinition.name}_${keyDefinition.key}` as StorageKey;
+}

libs/common/src/platform/state/state-definition.ts

@@ -0,0 +1,13 @@
+export type StorageLocation = "disk" | "memory";
+
+/**
+ * Defines the base location and instruction of where this state is expected to be located.
+ */
+export class StateDefinition {
+  /**
+   * Creates a new instance of {@link StateDefinition}, the creation of which is owned by the platform team.
+   * @param name The name of the state, this needs to be unique from all other {@link StateDefinition}'s.
+   * @param storageLocation The location of where this state should be stored.
+   */
+  constructor(readonly name: string, readonly storageLocation: StorageLocation) {}
+}

libs/common/src/platform/state/user-state.provider.ts

@@ -0,0 +1,13 @@
+import { KeyDefinition } from "./key-definition";
+import { UserState } from "./user-state";
+
+/**
+ * A provider for getting an implementation of user scoped state for the given key.
+ */
+export abstract class UserStateProvider {
+  /**
+   * Gets a {@link GlobalState} scoped to the given {@link KeyDefinition}
+   * @param keyDefinition - The {@link KeyDefinition} for which you want the user state for.
+   */
+  get: <T>(keyDefinition: KeyDefinition<T>) => UserState<T>;
+}

libs/common/src/platform/state/user-state.ts

@@ -0,0 +1,41 @@
+import { Observable } from "rxjs";
+
+import { UserId } from "../../types/guid";
+import { EncryptService } from "../abstractions/encrypt.service";
+import { UserKey } from "../models/domain/symmetric-crypto-key";
+
+import { DerivedUserState } from ".";
+
+export class DeriveContext {
+  constructor(readonly activeUserKey: UserKey, readonly encryptService: EncryptService) {}
+}
+
+export type Converter<TFrom, TTo> = (data: TFrom, context: DeriveContext) => Promise<TTo>;
+
+/**
+ * A helper object for interacting with state that is scoped to a specific user.
+ */
+export interface UserState<T> {
+  readonly state$: Observable<T>;
+  readonly getFromState: () => Promise<T>;
+  /**
+   * Updates backing stores for the active user.
+   * @param configureState function that takes the current state and returns the new state
+   * @returns The new state
+   */
+  readonly update: (configureState: (state: T) => T) => Promise<T>;
+  /**
+   * Updates backing stores for the given userId, which may or may not be active.
+   * @param userId the UserId to target the update for
+   * @param configureState function that takes the current state for the targeted user and returns the new state
+   * @returns The new state
+   */
+  readonly updateFor: (userId: UserId, configureState: (state: T) => T) => Promise<T>;
+
+  /**
+   * Creates a derives state from the current state. Derived states are always tied to the active user.
+   * @param converter
+   * @returns
+   */
+  createDerived: <TTo>(converter: Converter<T, TTo>) => DerivedUserState<TTo>;
+}

libs/node/jest.config.js

@@ -8,6 +8,7 @@ const sharedConfig = require("../shared/jest.config.ts");
 module.exports = {
   ...sharedConfig,
   preset: "ts-jest",
+  testEnvironment: "node",
   setupFilesAfterEnv: ["<rootDir>/test.setup.ts"],
   moduleNameMapper: pathsToModuleNameMapper(compilerOptions?.paths || {}, {
     prefix: "<rootDir>/",

libs/shared/test.environment.ts

@@ -0,0 +1,22 @@
+import JSDOMEnvironment from "jest-environment-jsdom";
+
+/**
+ * https://github.com/jsdom/jsdom/issues/3363#issuecomment-1467894943
+ * Adds nodes structuredClone implementation to the global object of jsdom.
+ * use by either adding this file to the testEnvironment property of jest config
+ * or by adding the following to the top spec file:
+ *
+ * ```
+ * /**
+ *  * @jest-environment ../shared/test.environment.ts
+ *  *\/
+ * ```
+ */
+export default class FixJSDOMEnvironment extends JSDOMEnvironment {
+  constructor(...args: ConstructorParameters<typeof JSDOMEnvironment>) {
+    super(...args);
+
+    // FIXME https://github.com/jsdom/jsdom/issues/3363
+    this.global.structuredClone = structuredClone;
+  }
+}