iterama/node/zip-async.js

Composable functional (async) iterable helpers

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.zipAsync = zipAsync;

function zipAsync(...iterables) {
  return {
    async *[Symbol.asyncIterator]() {
      const iterators = iterables.map(i => i[Symbol.asyncIterator]());

      try {
        while (true) {
          const values = await Promise.all(iterators.map(i => i.next()));

          if (values.some(v => v.done)) {
            break;
          }

          yield values.map(v => v.value);
        }
      } finally {
        await Promise.all(iterators.map(i => {
          var _i$return;

          return (_i$return = i.return) === null || _i$return === void 0 ? void 0 : _i$return.call(i);
        }));
      }
    }

  };
}