feat(workerd): stream eval

packages/workerd/src/plugin.ts

@@ -205,9 +205,12 @@ export async function createWorkerdDevEnvironment(
         JSON.stringify({
           entry: ctx.entry,
           fnString: ctx.fn.toString(),
+          stream: ctx.stream,
         } satisfies EvalMetadata),
       );
-      const body = JSON.stringify(ctx.data ?? (null as any));
+      const body: any = ctx.stream
+        ? ctx.data
+        : JSON.stringify(ctx.data ?? (null as any));
       const fetch_ = runnerObject.fetch as any as typeof fetch; // fix web/undici types
       const response = await fetch_(ANY_URL + RUNNER_EVAL_PATH, {
         method: "POST",
@@ -217,8 +220,8 @@ export async function createWorkerdDevEnvironment(
         duplex: "half",
       });
       tinyassert(response.ok);
-      const result = await response.json();
-      return result as any;
+      const result: any = ctx.stream ? response.body : await response.json();
+      return result;
     },
   };
 

packages/workerd/src/shared.ts

@@ -30,9 +30,11 @@ export type EvalApi = <In = any, Out = any>(request: {
   entry: string;
   data?: In;
   fn: EvalFn<In, Out>;
+  stream?: boolean;
 }) => Promise<Awaited<Out>>;
 
 export type EvalMetadata = {
   entry: string;
   fnString: string;
+  stream?: boolean;
 };

packages/workerd/src/worker.ts

@@ -48,13 +48,13 @@ export class RunnerObject implements DurableObject {
         request.headers.get("x-vite-eval")!,
       ) as EvalMetadata;
       const mod = await this.#runner.import(meta.entry);
-      const data = await request.json();
+      const data = meta.stream ? request.body : await request.json();
       const env = objectPickBy(this.#env, (_v, k) => !k.startsWith("__vite"));
       const fn: EvalFn = this.#env.__viteUnsafeEval.eval(
         `() => ${meta.fnString}`,
       )();
       const result = await fn({ mod, data, env, runner: this.#runner });
-      const body = JSON.stringify(result ?? null);
+      const body = meta.stream ? result : JSON.stringify(result ?? null);
       return new Response(body);
     }