async-from-sync-iterator.js 2.2 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960
  1. 'use strict';
  2. var call = require('../internals/function-call');
  3. var anObject = require('../internals/an-object');
  4. var create = require('../internals/object-create');
  5. var getMethod = require('../internals/get-method');
  6. var defineBuiltIns = require('../internals/define-built-ins');
  7. var InternalStateModule = require('../internals/internal-state');
  8. var iteratorClose = require('../internals/iterator-close');
  9. var getBuiltIn = require('../internals/get-built-in');
  10. var AsyncIteratorPrototype = require('../internals/async-iterator-prototype');
  11. var createIterResultObject = require('../internals/create-iter-result-object');
  12. var Promise = getBuiltIn('Promise');
  13. var ASYNC_FROM_SYNC_ITERATOR = 'AsyncFromSyncIterator';
  14. var setInternalState = InternalStateModule.set;
  15. var getInternalState = InternalStateModule.getterFor(ASYNC_FROM_SYNC_ITERATOR);
  16. var asyncFromSyncIteratorContinuation = function (result, resolve, reject, syncIterator, closeOnRejection) {
  17. var done = result.done;
  18. Promise.resolve(result.value).then(function (value) {
  19. resolve(createIterResultObject(value, done));
  20. }, function (error) {
  21. if (!done && closeOnRejection) {
  22. try {
  23. iteratorClose(syncIterator, 'throw', error);
  24. } catch (error2) {
  25. error = error2;
  26. }
  27. }
  28. reject(error);
  29. });
  30. };
  31. var AsyncFromSyncIterator = function AsyncIterator(iteratorRecord) {
  32. iteratorRecord.type = ASYNC_FROM_SYNC_ITERATOR;
  33. setInternalState(this, iteratorRecord);
  34. };
  35. AsyncFromSyncIterator.prototype = defineBuiltIns(create(AsyncIteratorPrototype), {
  36. next: function next() {
  37. var state = getInternalState(this);
  38. return new Promise(function (resolve, reject) {
  39. var result = anObject(call(state.next, state.iterator));
  40. asyncFromSyncIteratorContinuation(result, resolve, reject, state.iterator, true);
  41. });
  42. },
  43. 'return': function () {
  44. var iterator = getInternalState(this).iterator;
  45. return new Promise(function (resolve, reject) {
  46. var $return = getMethod(iterator, 'return');
  47. if ($return === undefined) return resolve(createIterResultObject(undefined, true));
  48. var result = anObject(call($return, iterator));
  49. asyncFromSyncIteratorContinuation(result, resolve, reject, iterator);
  50. });
  51. }
  52. });
  53. module.exports = AsyncFromSyncIterator;