RPC

shared/rpc-client.ts

@@ -9,7 +9,10 @@ export class StateClient {
   private cache: { chainId: string; blocks: TestnetBlock[]; bytes: number } | undefined;
   private inFlight: Promise<TestnetSnapshot> | undefined;
   private readonly fetcher: typeof fetch;
-  constructor(fetcher: typeof fetch = fetch) { this.fetcher = fetcher; }
+  constructor(fetcher: typeof fetch = globalThis.fetch) {
+    // Browser Web APIs require the Window/global receiver, not this StateClient instance.
+    this.fetcher = fetcher.bind(globalThis);
+  }
   async json<T>(path: string, signal: AbortSignal): Promise<T> {
     const response = await this.fetcher(`/api/${path}`, { cache: 'no-store', redirect: 'error', signal });
     if (!/^application\/json(?:\s*;|$)/i.test(response.headers.get('content-type') ?? '') || !response.body) throw new Error('Node must return JSON.');