diff --git a/js/util.js b/js/util.js
index 885d777..4d310f0 100644
--- a/js/util.js
+++ b/js/util.js
@@ -378,7 +378,7 @@ export class FileSource {
     async get(path) {}
 
     // Get a list of all files under here, recursively
-    async *iter_all_files() {}
+    // async *iter_all_files() {}
 }
 // Files we have had uploaded one at a time (note that each upload becomes its own source)
 export class FileFileSource extends FileSource {
@@ -542,4 +542,8 @@ export class ZipFileSource extends FileSource {
 
         return file.buffer;
     }
+
+    iter_all_files() {
+        return Object.keys(this.files);
+    }
 }