fix(fusuma): allow undefined for gzSize

Author: hiroppy

README.md

@@ -197,13 +197,11 @@ You can see your Note for each slide and the next slide on the Host screen.
 
 > [Lighthouse](https://developers.google.com/web/tools/lighthouse) is an open-source, automated tool for improving the quality of web pages. You can run it against any web page, public or requiring authentication. It has audits for performance, accessibility, progressive web apps, SEO and more.
 
-Fusuma supports improving performance, SEO, and so on as default.
+Fusuma supports improving performance, SEO, and so on as default, analyzes the slide's performance, and outputs like below.
 
-<img src="./site/docs/assets/lighthouse.png" width="500px">
-
-Fusuma analyzes the slide's performance, and outputs like below.
-
-<img src="./output-logs.png" width="500px">
+|        the score of lighthouse         |      output logs       |
+| :------------------------------------: | :--------------------: |
+| ![](./site/docs/assets/lighthouse.png) | ![](./output-logs.png) |
 
 ---
 

output-logs.png

@@ -155,7 +155,7 @@ function buildLogs(logs) {
           isAsync ? asyncChunk : syncChunk
         } ${name}`,
         chalk.blue(prettyBytes(size)),
-        gzSize !== 0 ? chalk.blue(prettyBytes(gzSize)) : '',
+        gzSize ? chalk.blue(prettyBytes(gzSize)) : '',
       ]);
     });