diff --git a/src/api.ts b/src/api.ts
index 743bea4..cf6e1fe 100644
--- a/src/api.ts
+++ b/src/api.ts
@@ -1,7 +1,6 @@
 import { intro, outro } from '@clack/prompts';
 import {
   ChatCompletionRequestMessage,
-  ChatCompletionResponseMessage,
   Configuration as OpenAiApiConfiguration,
   OpenAIApi
 } from 'openai';
@@ -43,7 +42,7 @@ class OpenAi {
 
   public generateCommitMessage = async (
     messages: Array<ChatCompletionRequestMessage>
-  ): Promise<ChatCompletionResponseMessage | undefined> => {
+  ): Promise<string | undefined> => {
     try {
       const { data } = await this.openAI.createChatCompletion({
         model: 'gpt-3.5-turbo',
@@ -55,7 +54,7 @@ class OpenAi {
 
       const message = data.choices[0].message;
 
-      return message;
+      return message?.content;
     } catch (error) {
       console.error('openAI api error', { error });
       throw error;
diff --git a/src/generateCommitMessageFromGitDiff.ts b/src/generateCommitMessageFromGitDiff.ts
index 6c09479..c3fb638 100644
--- a/src/generateCommitMessageFromGitDiff.ts
+++ b/src/generateCommitMessageFromGitDiff.ts
@@ -92,17 +92,18 @@ export const generateCommitMessageWithChatCompletion = async (
 
       const diffByFiles = diff.split(separator).slice(1);
 
-      const commitMessagePromises = diffByFiles.map((fileDiff) => {
-        // TODO: split by files
-        if (INIT_MESSAGES_PROMPT_LENGTH + fileDiff.length >= MAX_REQ_TOKENS)
-          return null;
+      const commitMessagePromises = diffByFiles
+        .map((fileDiff) => {
+          // TODO: split by files
+          if (fileDiff.length >= MAX_REQ_TOKENS) return null;
 
-        const messages = generateCommitMessageChatCompletionPrompt(
-          separator + fileDiff
-        );
+          const messages = generateCommitMessageChatCompletionPrompt(
+            separator + fileDiff
+          );
 
-        return api.generateCommitMessage(messages);
-      });
+          return api.generateCommitMessage(messages);
+        })
+        .filter(Boolean);
 
       const commitMessages = await Promise.all(commitMessagePromises);
 
@@ -116,7 +117,7 @@ export const generateCommitMessageWithChatCompletion = async (
     if (!commitMessage)
       return { error: GenerateCommitMessageErrorEnum.emptyMessage };
 
-    return commitMessage.content;
+    return commitMessage;
   } catch (error) {
     return { error: GenerateCommitMessageErrorEnum.internalError };
   }
diff --git a/tsconfig.json b/tsconfig.json
index 6dedf1a..ca6f857 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -1,6 +1,6 @@
 {
   "compilerOptions": {
-    "target": "ESNext",
+    "target": "ES2020",
     "lib": ["ES5", "ES6"],
 
     "module": "ESNext",