[Fix] Issue with subdirectory passing

Resolved an issue where listing would sometimes return empty filepaths.
References #18.

server/src/code-snippets/controllers/code-snippets.controller.ts

@@ -12,7 +12,7 @@ import { CodeSnippetsService } from '../services/code-snippets.service';
 export class CodeSnippetsController {
   constructor(private readonly codeSnippetsService: CodeSnippetsService) {}
 
-  @Get(':subdirectory(*)')
+  @Get(':subdirectory(*)|/')
   @UseGuards(AuthSessionGuard)
   @ApiCookieAuth()
   @ApiOkResponse({ description: 'Tree of user files.' })
@@ -23,7 +23,7 @@ export class CodeSnippetsController {
   ) {
     return this.codeSnippetsService.listUserCodeSnippets(
       req.user['username'],
-      subdirectory,
+      subdirectory ?? '',
     );
   }
 }

server/src/code-snippets/services/code-snippets.service.ts

@@ -9,10 +9,17 @@ export class CodeSnippetsService {
 
   async listUserCodeSnippets(username: string, subdirectory?: string) {
     const tree = {};
+    const prefix = `${username}/${
+      subdirectory
+        ? subdirectory.endsWith('/')
+          ? subdirectory
+          : subdirectory + '/'
+        : ''
+    }`;
     const queryResponse = await this.s3
       .listObjectsV2({
         Bucket: configObject.aws.codeSnippetsS3Bucket,
-        Prefix: `${username}/${subdirectory ?? ''}`,
+        Prefix: prefix,
       })
       .promise();
 
@@ -30,7 +37,7 @@ export class CodeSnippetsService {
     // Each such array is being iterated over a recursive function which keeps nesting
     // items (strings from the array) until the last one is reached.
     queryResponse.Contents.filter((item) => !item.Key.endsWith('/'))
-      .map((item) => item.Key.replace(`${username}/`, '').split('/'))
+      .map((item) => item.Key.replace(prefix, '').split('/'))
       .forEach((item) => this.addToFileTree(tree, item));
 
     return tree;