1 files changed, 84 insertions, 0 deletions
diff --git a/remote/test/puppeteer/packages/puppeteer-core/src/common/HandleIterator.ts b/remote/test/puppeteer/packages/puppeteer-core/src/common/HandleIterator.ts
new file mode 100644
index 0000000000..d5df382f88
--- /dev/null
+++ b/remote/test/puppeteer/packages/puppeteer-core/src/common/HandleIterator.ts
@@ -0,0 +1,84 @@
+/**
+ * Copyright 2023 Google Inc. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import {JSHandle} from '../api/JSHandle.js';
+
+import {AwaitableIterable, HandleFor} from './types.js';
+
+const DEFAULT_BATCH_SIZE = 20;
+
+/**
+ * This will transpose an iterator JSHandle into a fast, Puppeteer-side iterator
+ * of JSHandles.
+ *
+ * @param size - The number of elements to transpose. This should be something
+ * reasonable.
+ */
+async function* fastTransposeIteratorHandle<T>(
+  iterator: JSHandle<AwaitableIterator<T>>,
+  size: number
+) {
+  const array = await iterator.evaluateHandle(async (iterator, size) => {
+    const results = [];
+    while (results.length < size) {
+      const result = await iterator.next();
+      if (result.done) {
+        break;
+      }
+      results.push(result.value);
+    }
+    return results;
+  }, size);
+  const properties = (await array.getProperties()) as Map<string, HandleFor<T>>;
+  await array.dispose();
+  yield* properties.values();
+  return properties.size === 0;
+}
+
+/**
+ * This will transpose an iterator JSHandle in batches based on the default size
+ * of {@link fastTransposeIteratorHandle}.
+ */
+
+async function* transposeIteratorHandle<T>(
+  iterator: JSHandle<AwaitableIterator<T>>
+) {
+  let size = DEFAULT_BATCH_SIZE;
+  try {
+    while (!(yield* fastTransposeIteratorHandle(iterator, size))) {
+      size <<= 1;
+    }
+  } finally {
+    await iterator.dispose();
+  }
+}
+
+type AwaitableIterator<T> = Iterator<T> | AsyncIterator<T>;
+
+/**
+ * @internal
+ */
+export async function* transposeIterableHandle<T>(
+  handle: JSHandle<AwaitableIterable<T>>
+): AsyncIterableIterator<HandleFor<T>> {
+  yield* transposeIteratorHandle(
+    await handle.evaluateHandle(iterable => {
+      return (async function* () {
+        yield* iterable;
+      })();
+    })
+  );
+}