qwtel · October 12, 2020 09:02 · Oct 12, 2020
diff --git a/whatwg-stream-to-async-iterable.ts b/whatwg-stream-to-async-iterable.ts
@@ -0,0 +1,21 @@
+export async function* streamToAsyncIterable<T>(stream: ReadableStream<T>): AsyncIterableIterator<T> {
+  const reader = stream.getReader();
+  try {
+    while (true) {
+      const { done, value } = await reader.read();
+      if (done) return;
+      yield value;
+    }
+  } finally { reader.releaseLock() }
+}
+
+export function asyncIterableToStream<T>(asyncIterable: AsyncIterable<T>): ReadableStream<T> {
+  const { readable, writable } = new TransformStream<T, T>();
+  (async () => {
+    const writer = writable.getWriter();
+    try {
+      for await (const x of asyncIterable) writer.write(x);
+    } finally { writer.close() }
+  })();
+  return readable;
+}