function _defineProperty(obj, key, value) { if (key in obj) { Object.defineProperty(obj, key, { value: value, enumerable: true, configurable: true, writable: true }); } else { obj[key] = value; } return obj; } import { SYMBOL_ASYNC_ITERATOR } from "../polyfills/symbols.mjs"; /** * Given an AsyncIterable and a callback function, return an AsyncIterator * which produces values mapped via calling the callback function. */ export default function mapAsyncIterator(iterable, callback, rejectCallback) { // $FlowFixMe[prop-missing] var iteratorMethod = iterable[SYMBOL_ASYNC_ITERATOR]; var iterator = iteratorMethod.call(iterable); var $return; var abruptClose; if (typeof iterator.return === 'function') { $return = iterator.return; abruptClose = function abruptClose(error) { var rethrow = function rethrow() { return Promise.reject(error); }; return $return.call(iterator).then(rethrow, rethrow); }; } function mapResult(result) { return result.done ? result : asyncMapValue(result.value, callback).then(iteratorResult, abruptClose); } var mapReject; if (rejectCallback) { // Capture rejectCallback to ensure it cannot be null. var reject = rejectCallback; mapReject = function mapReject(error) { return asyncMapValue(error, reject).then(iteratorResult, abruptClose); }; } /* TODO: Flow doesn't support symbols as keys: https://github.com/facebook/flow/issues/3258 */ return _defineProperty({ next: function next() { return iterator.next().then(mapResult, mapReject); }, return: function _return() { return $return ? $return.call(iterator).then(mapResult, mapReject) : Promise.resolve({ value: undefined, done: true }); }, throw: function _throw(error) { if (typeof iterator.throw === 'function') { return iterator.throw(error).then(mapResult, mapReject); } return Promise.reject(error).catch(abruptClose); } }, SYMBOL_ASYNC_ITERATOR, function () { return this; }); } function asyncMapValue(value, callback) { return new Promise(function (resolve) { return resolve(callback(value)); }); } function iteratorResult(value) { return { value: value, done: false }; }