feat: playground add submenu

src/utils/epub-reader.ts

@@ -0,0 +1,29 @@
+import ePub from 'epubjs';
+
+export default function readEpubContent(file: File): Promise<string> {
+  return new Promise((resolve, reject) => {
+    const reader = new FileReader();
+    reader.onload = function (e: any) {
+      const arrayBuffer = e.target.result;
+      const book = ePub(arrayBuffer);
+
+      book.loaded?.spine?.then?.((spine: any) => {
+        const chapterPromises = spine.spineItems?.map?.((chapter: any) => {
+          return book.load(chapter.href).then((content: any) => {
+            return content.body?.textContent || '';
+          });
+        });
+        Promise.all(chapterPromises)
+          .then((chaptersText) => {
+            const result = chaptersText.join('');
+            resolve(result);
+          })
+          .catch((error) => {
+            reject(error);
+          });
+      });
+    };
+    reader.onerror = (error) => reject(error);
+    reader.readAsArrayBuffer(file);
+  });
+}