file zip bug fixed

src/file.js

@@ -31,7 +31,15 @@ export class File {
     const parts = this.makeParts();
     const zip = new Zip();
     for (const key of Object.keys(parts)) {
-      zip.file(key, parts[key]);
+      const paths = key.split('/');
+      console.log(paths);
+      const folders = paths.slice(0, -1);
+      const filename = paths[paths.length - 1];
+      const folder = folders.reduce(function (parent, name) {
+        return parent.folder(name);
+      }, zip);
+
+      folder.file(filename, parts[key]);
     }
     if (type === 'blob' || type === 'base64') {
       return zip.generateAsync({ type });