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/**
* @license
* Copyright 2023 Google Inc.
* SPDX-License-Identifier: Apache-2.0
*/
import type {JSHandle} from '../api/JSHandle.js';
import {DisposableStack, disposeSymbol} from '../util/disposable.js';
import type {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
) {
using 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>>;
const handles = properties.values();
using stack = new DisposableStack();
stack.defer(() => {
for (using handle of handles) {
handle[disposeSymbol]();
}
});
yield* handles;
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;
while (!(yield* fastTransposeIteratorHandle(iterator, size))) {
size <<= 1;
}
}
type AwaitableIterator<T> = Iterator<T> | AsyncIterator<T>;
/**
* @internal
*/
export async function* transposeIterableHandle<T>(
handle: JSHandle<AwaitableIterable<T>>
): AsyncIterableIterator<HandleFor<T>> {
using generatorHandle = await handle.evaluateHandle(iterable => {
return (async function* () {
yield* iterable;
})();
});
yield* transposeIteratorHandle(generatorHandle);
}