chore(core-api/Storage): Fixing some code review comments, so we don't have to cast some stuff in Typescript

packages/core-api/src/apis/definitions/StorageApi.ts

@@ -17,21 +17,21 @@
 import { createApiRef } from '../ApiRef';
 import { Observable } from '../../types';
 
-export type ObservableMessage<T extends object = {}> = {
+export type ObservableMessage<T = any> = {
   key: string;
   newValue?: T;
 };
 
 export interface StorageApi {
   /**
-   * The names
+   * Create a bucket to store data in.
    * @param {String} name Namespace for the storage to be stored under,
    *                      will inherit previous namespaces too
    */
   forBucket(name: string): StorageApi;
 
   /**
-   * Get persistent data.
+   * Get the current value for persistent data, use observe$ to be notified of updates.
    *
    * @param {String} key Unique key associated with the data.
    * @return {Object} data The data that should is stored.
@@ -46,17 +46,17 @@ export interface StorageApi {
   remove(key: string): Promise<void>;
 
   /**
-   * Save persistant data.
+   * Save persistant data, and emit messages to anyone that is using observe$ for this key
    *
    * @param {String} key Unique key associated with the data.
    */
   set(key: string, data: any): Promise<void>;
 
   /**
-   *
+   * Observe changes on a particular key in the bucket
    * @param {String} key Unique key associated with the data
    */
-  observe$<T>(key: string): Observable<T>;
+  observe$<T>(key: string): Observable<ObservableMessage<T>>;
 }
 
 export const storageApiRef = createApiRef<StorageApi>({

packages/core-api/src/apis/implementations/StorageApi/WebStorage.ts

@@ -48,17 +48,15 @@ export class WebStorage implements StorageApi {
     this.notifyChanges({ key, newValue: undefined });
   }
 
-  observe$<T>(key: string): Observable<T> {
-    return this.observable.filter(
-      ({ key: messageKey }) => messageKey === key,
-    ) as Observable<T>;
+  observe$<T>(key: string): Observable<ObservableMessage<T>> {
+    return this.observable.filter(({ key: messageKey }) => messageKey === key);
   }
 
   private getKeyName(key: string) {
     return `${this.namespace}/${key}`;
   }
 
-  private notifyChanges(message: ObservableMessage) {
+  private notifyChanges<T>(message: ObservableMessage<T>) {
     for (const subscription of this.subscribers) {
       subscription.next(message);
     }