diff --git a/app.js b/app.js
index e5b6b400..df1c25b8 100644
--- a/app.js
+++ b/app.js
@@ -1,8 +1,8 @@
-'use strict';
-const fs = require('fs');
-const fileName = './test.txt';
+"use strict";
+const fs = require("fs");
+const fileName = "./test.txt";
 for (let count = 0; count < 30; count++) {
-    fs.appendFile(fileName, 'おはようございます\n', 'utf8', () => {});
-    fs.appendFile(fileName, 'こんにちは\n', 'utf8', () => {});
-    fs.appendFile(fileName, 'こんばんは\n', 'utf8', () => {});
+  fs.appendFileSync(fileName, "おはようございます\n", "utf8", () => {});
+  fs.appendFileSync(fileName, "こんにちは\n", "utf8", () => {});
+  fs.appendFileSync(fileName, "こんばんは\n", "utf8", () => {});
 }