export function* zip<T extends Array<unknown>>(

...iterables: { [K in keyof T]: Iterable<T[K]> }

): Iterable<{ [K in keyof T]: T[K] | undefined }> {

const iterators = iterables.map((iterable) => iterable[Symbol.iterator]());

while (true) {

const values = [];

let hasMore = false;

for (const iterator of iterators) {

const { done, value } = iterator.next();

hasMore ||= !done;

values.push(value);

}

if (!hasMore) {

return;

}

yield values as T;

}

}

export async function* zipAsync<T extends Array<unknown>>(

...iterables: { [K in keyof T]: AsyncIterable<T[K]> }

): AsyncIterable<{ [K in keyof T]: T[K] | undefined }> {

const iterators = iterables.map((iterable) =>

iterable[Symbol.asyncIterator]()

);

while (true) {

const values = [];

let hasMore = false;

for (const iterator of iterators) {

const { done, value } = await iterator.next();

hasMore ||= !done;

values.push(value);

}

if (!hasMore) {

return;

}

yield values as T;

}

}