diff --git a/src/frontend/apps/impress/src/features/docs/doc-editor/utils.ts b/src/frontend/apps/impress/src/features/docs/doc-editor/utils.ts
index aa0d43ba..a3d31118 100644
--- a/src/frontend/apps/impress/src/features/docs/doc-editor/utils.ts
+++ b/src/frontend/apps/impress/src/features/docs/doc-editor/utils.ts
@@ -23,6 +23,5 @@ function hslToHex(h: number, s: number, l: number) {
   return `#${f(0)}${f(8)}${f(4)}`;
 }
 
-export const toBase64 = (
-  str: WithImplicitCoercion<ArrayBuffer | SharedArrayBuffer>,
-) => Buffer.from(str).toString('base64');
+export const toBase64 = (str: Uint8Array) =>
+  Buffer.from(str).toString('base64');
diff --git a/src/frontend/apps/impress/src/features/service-worker/RequestSerializer.ts b/src/frontend/apps/impress/src/features/service-worker/RequestSerializer.ts
index 3b347c2d..427ecee4 100644
--- a/src/frontend/apps/impress/src/features/service-worker/RequestSerializer.ts
+++ b/src/frontend/apps/impress/src/features/service-worker/RequestSerializer.ts
@@ -2,7 +2,7 @@ export type RequestData = {
   url: string;
   method?: string;
   headers: Record<string, string>;
-  body?: ArrayBuffer;
+  body?: ArrayBufferLike;
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
   [key: string]: any;
 };
@@ -48,12 +48,12 @@ export class RequestSerializer {
     return new RequestSerializer(requestData);
   }
 
-  public static arrayBufferToString(buffer: ArrayBuffer) {
+  public static arrayBufferToString(buffer: ArrayBufferLike) {
     const decoder = new TextDecoder();
-    return decoder.decode(buffer);
+    return decoder.decode(buffer as ArrayBuffer);
   }
 
-  public static arrayBufferToJson<T>(buffer: ArrayBuffer) {
+  public static arrayBufferToJson<T>(buffer: ArrayBufferLike) {
     const jsonString = RequestSerializer.arrayBufferToString(buffer);
     return JSON.parse(jsonString) as T;
   }
@@ -64,7 +64,9 @@ export class RequestSerializer {
   }
 
   public static objectToArrayBuffer(ob: Record<string, unknown>) {
-    return RequestSerializer.stringToArrayBuffer(JSON.stringify(ob));
+    return RequestSerializer.stringToArrayBuffer(
+      JSON.stringify(ob),
+    ) as ArrayBuffer;
   }
 
   constructor(requestData: RequestData) {
@@ -85,7 +87,7 @@ export class RequestSerializer {
 
   toRequest(): Request {
     const { url, ...rest } = this._requestData;
-    return new Request(url, rest);
+    return new Request(url, { ...rest, body: rest.body as BodyInit });
   }
 
   clone(): RequestSerializer {