[Mgt-File] Fix FolderName with dot, fix upper case file extension, Fix file without extension (#1146)

* [Mgt-File] Fix FolderName with dot, fix upper case file extension, Fix file without extensions.

* prettier:write

Co-authored-by: Nikola Metulev <[email protected]>
Co-authored-by: Nikola Metulev <[email protected]>

Author: aaclage

packages/mgt-components/src/components/mgt-file/mgt-file.ts

@@ -489,12 +489,15 @@ export class MgtFile extends MgtTemplatedComponent {
       // get file type extension from file name
       const re = /(?:\.([^.]+))?$/;
       const fileType =
-        re.exec(this.driveItem.name)[1] ||
-        (this.driveItem.package !== undefined
+        this.driveItem.package === undefined && this.driveItem.folder === undefined
+          ? re.exec(this.driveItem.name)[1]
+            ? re.exec(this.driveItem.name)[1].toLowerCase()
+            : 'null'
+          : this.driveItem.package !== undefined
           ? this.driveItem.package.type === 'oneNote'
             ? 'onetoc'
             : 'folder'
-          : 'folder');
+          : 'folder';
       fileIconSrc = getFileTypeIconUriByExtension(fileType, 48, 'svg');
     }