sentence database builder script

docs/.vitepress/vite-plugins/gtts.ts

@@ -49,11 +49,17 @@ async function gtts(
     fileList = JSON.parse(fs.readFileSync(fileListJSON, "utf-8"));
   }
 
-  const fileNo = fileList[text] || Object.keys(fileList).length;
+  let fileNo = fileList[text];
+
+  let isFileNoExists = Number.isInteger(fileNo);
+  if (!isFileNoExists) {
+    fileNo = Math.max(0, ...Object.values(fileList)) + 1;
+  }
+
   const filename = `${fileNo}.mp3`;
   const saveto = path.join(saveroot, filename);
 
-  if (!fs.existsSync(saveto)) {
+  if (!isFileNoExists || !fs.existsSync(saveto)) {
     await new Promise((resolve, reject) => {
       const p = spawn(
         "gtts-cli",