Add recursive firing of dispose events of sub directory deletion

packages/dds/map/src/directory.ts

@@ -1537,7 +1537,27 @@ 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;
+        }
+        const stack: [{node: IDirectory, visited: boolean}] = [{node: directory, visited: false}];
+        while (stack.length > 0) {
+            const node = stack.pop();
+            assert(node !== undefined, "Sub directory should be present");
+            if (node.visited) {
+                node.node.dispose();
+            } else {
+                stack.push({node: node.node, visited: true});
+                const subDirectories = node.node.subdirectories();
+                for (const [_, subDirectory] of subDirectories) {
+                    stack.push({node: subDirectory, visited: false});
+                }
+            }
+        }
+    }
 }

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", () => {