feat(watcher): Enhance change stream watchers with buffering and EventEmitter support; update dependency versions

ts/classes.collection.ts

@@ -256,24 +256,40 @@ export class SmartdataCollection<T> {
   }
 
   /**
-   * watches the collection while applying a filter
+   * Watches the collection, returning a SmartdataDbWatcher with RxJS and EventEmitter support.
+   * @param filterObject match filter for change stream
+   * @param opts optional MongoDB ChangeStreamOptions & { bufferTimeMs } to buffer events
+   * @param smartdataDbDocArg document class for instance creation
    */
   public async watch(
     filterObject: any,
-    smartdataDbDocArg: typeof SmartDataDbDoc,
+    opts: (plugins.mongodb.ChangeStreamOptions & { bufferTimeMs?: number }) = {},
+    smartdataDbDocArg?: typeof SmartDataDbDoc,
   ): Promise<SmartdataDbWatcher> {
     await this.init();
+    // Extract bufferTimeMs from options
+    const { bufferTimeMs, fullDocument, ...otherOptions } = opts || {};
+    // Determine fullDocument behavior: default to 'updateLookup'
+    const changeStreamOptions: plugins.mongodb.ChangeStreamOptions = {
+      ...otherOptions,
+      fullDocument:
+        fullDocument === undefined
+          ? 'updateLookup'
+          : fullDocument === true
+          ? 'updateLookup'
+          : fullDocument,
+    } as any;
+    // Build pipeline with match if provided
+    const pipeline = filterObject ? [{ $match: filterObject }] : [];
     const changeStream = this.mongoDbCollection.watch(
-      [
-        {
-          $match: filterObject,
-        },
-      ],
-      {
-        fullDocument: 'updateLookup',
-      },
+      pipeline,
+      changeStreamOptions,
+    );
+    const smartdataWatcher = new SmartdataDbWatcher(
+      changeStream,
+      smartdataDbDocArg,
+      { bufferTimeMs },
     );
-    const smartdataWatcher = new SmartdataDbWatcher(changeStream, smartdataDbDocArg);
     await smartdataWatcher.readyDeferred.promise;
     return smartdataWatcher;
   }