diff --git a/lib/es9.js b/lib/es9.js
index f81c9d0..f336637 100644
--- a/lib/es9.js
+++ b/lib/es9.js
@@ -1,10 +1,7 @@
 async function* asyncPool(concurrency, iterable, iteratorFn) {
-  let done;
-  const ret = [];
   const executing = new Set();
   for (const item of iterable) {
     const promise = Promise.resolve().then(() => iteratorFn(item, iterable));
-    ret.push(promise);
     executing.add(promise);
     const clean = () => executing.delete(promise);
     promise.then(clean).catch(clean);