Update app.js

@@ -87,6 +87,7 @@ async function handleEvent(event) {
       .then(
         async(stream) => {
           await stream.on('data', (chunk) => {
+            console.log(typeof(chunk));
             fs.writeFileSync('./photo/1.png',chunk);
       var cheerio = require('cheerio');
       var uriBase = 'https://koreacentral.api.cognitive.microsoft.com/vision/v2.1/ocr';