fix(core): update

ts/smartbucket.classes.directory.ts

@@ -123,9 +123,11 @@ export class Directory {
   /**
    * gets a sub directory
    */
-  public async getSubDirectory(): Promise<Directory> {
-    return this;
-    // TODO
+  public async getSubDirectoryByName(dirNameArg: string): Promise<Directory> {
+    const directories = await this.listDirectories();
+    return directories.find(directory => {
+      return directory.name === dirNameArg;
+    });
   }
 
   /**