Add recursive firing of dispose events of sub directory deletion (mic…

…rosoft#9451)

packages/dds/map/src/directory.ts

@@ -1537,7 +1537,19 @@ class SubDirectory extends TypedEventEmitter<IDirectoryEvents> implements IDirec
         // This should make the subdirectory structure unreachable so it can be GC'd and won't appear in snapshots
         // Might want to consider cleaning out the structure more exhaustively though?
         const successfullyRemoved = this._subdirectories.delete(subdirName);
-        previousValue?.dispose();
+        this.disposeSubDirectoryTree(previousValue);
         return successfullyRemoved;
     }
+
+    private disposeSubDirectoryTree(directory: IDirectory | undefined) {
+        if (!directory) {
+            return;
+        }
+        // Dispose the subdirectory tree. This will dispose the subdirectories from bottom to top.
+        const subDirectories = directory.subdirectories();
+        for (const [_, subDirectory] of subDirectories) {
+            this.disposeSubDirectoryTree(subDirectory);
+        }
+        directory.dispose();
+    }
 }

packages/dds/map/src/test/directory.spec.ts

@@ -184,6 +184,22 @@ describe("Directory", () => {
                 } catch (error) {
                     assert.strictEqual(error.errorType, "usageError", "Should throw usage error");
                 }
+
+                // Check recursive dispose event firing
+                const subSubDirectory = newSubDirectory.createSubDirectory("rockChild");
+                let rockSubDirectoryDisposed = false;
+                let subSubDirectoryDisposed = false;
+                newSubDirectory.on("disposed", (value: IDirectory) => {
+                    rockSubDirectoryDisposed = true;
+                    assert.equal(value.disposed, true, "rock sub directory not deleted");
+                });
+                subSubDirectory.on("disposed", (value: IDirectory) => {
+                    subSubDirectoryDisposed = true;
+                    assert.equal(value.disposed, true, "sub sub directory not deleted");
+                });
+                directory.deleteSubDirectory("rock");
+                assert(rockSubDirectoryDisposed, "Rock sub directory should be disposed");
+                assert(subSubDirectoryDisposed, "sub sub directory should be disposed");
             });
 
             it("Rejects a undefined and null key set", () => {