diff --git a/src/api/endpoints/drive/files.ts b/src/api/endpoints/drive/files.ts
index eb0bfe6ba..41687c499 100644
--- a/src/api/endpoints/drive/files.ts
+++ b/src/api/endpoints/drive/files.ts
@@ -13,27 +13,27 @@ import serialize from '../../serializers/drive-file';
  * @param {any} app
  * @return {Promise<any>}
  */
-module.exports = (params, user, app) => new Promise(async (res, rej) => {
+module.exports = async (params, user, app) => {
 	// Get 'limit' parameter
 	const [limit = 10, limitErr] = $(params.limit).optional.number().range(1, 100).$;
-	if (limitErr) return rej('invalid limit param');
+	if (limitErr) throw 'invalid limit param';
 
 	// Get 'since_id' parameter
 	const [sinceId, sinceIdErr] = $(params.since_id).optional.id().$;
-	if (sinceIdErr) return rej('invalid since_id param');
+	if (sinceIdErr) throw 'invalid since_id param';
 
 	// Get 'max_id' parameter
 	const [maxId, maxIdErr] = $(params.max_id).optional.id().$;
-	if (maxIdErr) return rej('invalid max_id param');
+	if (maxIdErr) throw 'invalid max_id param';
 
 	// Check if both of since_id and max_id is specified
 	if (sinceId && maxId) {
-		return rej('cannot set since_id and max_id');
+		throw 'cannot set since_id and max_id';
 	}
 
 	// Get 'folder_id' parameter
 	const [folderId = null, folderIdErr] = $(params.folder_id).optional.nullable.id().$;
-	if (folderIdErr) return rej('invalid folder_id param');
+	if (folderIdErr) throw 'invalid folder_id param';
 
 	// Construct query
 	const sort = {
@@ -64,6 +64,6 @@ module.exports = (params, user, app) => new Promise(async (res, rej) => {
 		});
 
 	// Serialize
-	res(await Promise.all(files.map(async file =>
-		await serialize(file))));
-});
+	const _files = await Promise.all(files.map(file => serialize(file)));
+	return _files
+};
diff --git a/src/api/endpoints/drive/files/show.ts b/src/api/endpoints/drive/files/show.ts
index 9135a04c5..883034600 100644
--- a/src/api/endpoints/drive/files/show.ts
+++ b/src/api/endpoints/drive/files/show.ts
@@ -12,10 +12,10 @@ import serialize from '../../../serializers/drive-file';
  * @param {any} user
  * @return {Promise<any>}
  */
-module.exports = (params, user) => new Promise(async (res, rej) => {
+module.exports = async (params, user) => {
 	// Get 'file_id' parameter
 	const [fileId, fileIdErr] = $(params.file_id).id().$;
-	if (fileIdErr) return rej('invalid file_id param');
+	if (fileIdErr) throw 'invalid file_id param';
 
 	// Fetch file
 	const file = await DriveFile
@@ -27,11 +27,13 @@ module.exports = (params, user) => new Promise(async (res, rej) => {
 		});
 
 	if (file === null) {
-		return rej('file-not-found');
+		throw 'file-not-found';
 	}
 
 	// Serialize
-	res(await serialize(file, {
+	const _file = await serialize(file, {
 		detail: true
-	}));
-});
+	});
+
+	return _file
+};
diff --git a/src/api/endpoints/drive/folders/find.ts b/src/api/endpoints/drive/folders/find.ts
index cdf055839..a5eb8e015 100644
--- a/src/api/endpoints/drive/folders/find.ts
+++ b/src/api/endpoints/drive/folders/find.ts
@@ -30,6 +30,5 @@ module.exports = (params, user) => new Promise(async (res, rej) => {
 		});
 
 	// Serialize
-	res(await Promise.all(folders.map(async folder =>
-		await serialize(folder))));
+	res(await Promise.all(folders.map(folder => serialize(folder))));
 });
diff --git a/src/api/serializers/drive-file.ts b/src/api/serializers/drive-file.ts
index f98cdaa59..9858c3b3c 100644
--- a/src/api/serializers/drive-file.ts
+++ b/src/api/serializers/drive-file.ts
@@ -25,6 +25,8 @@ export default (
 		detail: false
 	}, options);
 
+	if (!file) return reject('invalid file arg.')
+
 	let _file: any;
 
 	// Populate the file if 'file' is ID