diff --git a/src/common.ts b/src/common.ts
index ff5975f..3963151 100644
--- a/src/common.ts
+++ b/src/common.ts
@@ -1,10 +1,13 @@
 export interface FileSystemSyncAccessHandle {
-  read: (container: ArrayBuffer, opts: { at: number }) => number;
-  write: (data: ArrayBuffer | ArrayBufferView, opts?: { at: number }) => number;
-  flush: () => void;
-  close: () => void;
-  truncate: (newSize: number) => void;
-  getSize: () => number;
+  read: (container: ArrayBuffer, opts: { at: number }) => Promise<number>;
+  write: (
+    data: ArrayBuffer | ArrayBufferView,
+    opts?: { at: number }
+  ) => Promise<number>;
+  flush: () => Promise<void>;
+  close: () => Promise<void>;
+  truncate: (newSize: number) => Promise<void>;
+  getSize: () => Promise<number>;
 }
 
 export function parsePath(path: string) {
diff --git a/src/opfs-worker.ts b/src/opfs-worker.ts
index b4dd79b..e2ff7c1 100644
--- a/src/opfs-worker.ts
+++ b/src/opfs-worker.ts
@@ -20,17 +20,18 @@ self.onmessage = async (e) => {
       accessHandle = await fh.createSyncAccessHandle();
       fileAccesserMap[args.filePath] = accessHandle;
     } else if (evtType === 'close') {
-      accessHandle.close();
+      await accessHandle.close();
       delete fileAccesserMap[args.filePath];
     } else if (evtType === 'truncate') {
-      accessHandle.truncate(args.newSize);
+      await accessHandle.truncate(args.newSize);
     } else if (evtType === 'write') {
       const { data, opts } = e.data.args;
-      returnVal = accessHandle.write(data, opts);
+      returnVal = await accessHandle.write(data, opts);
     } else if (evtType === 'read') {
       const { offset, size } = e.data.args;
-      const buf = new ArrayBuffer(size);
-      const readLen = accessHandle.read(buf, { at: offset });
+      const uint8Buf = new Uint8Array(size);
+      const readLen = await accessHandle.read(uint8Buf, { at: offset });
+      const buf = uint8Buf.buffer;
       returnVal =
         readLen === size
           ? buf
@@ -38,9 +39,9 @@ self.onmessage = async (e) => {
             buf.transfer?.(readLen) ?? buf.slice(0, readLen);
       trans.push(returnVal);
     } else if (evtType === 'getSize') {
-      returnVal = accessHandle.getSize();
+      returnVal = await accessHandle.getSize();
     } else if (evtType === 'flush') {
-      accessHandle.flush();
+      await accessHandle.flush();
     }
 
     self.postMessage(