async-from-sync-iterator.js 2.0 KB

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  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 getBuiltIn = require('../internals/get-built-in');
  9. var AsyncIteratorPrototype = require('../internals/async-iterator-prototype');
  10. var createIterResultObject = require('../internals/create-iter-result-object');
  11. var Promise = getBuiltIn('Promise');
  12. var ASYNC_FROM_SYNC_ITERATOR = 'AsyncFromSyncIterator';
  13. var setInternalState = InternalStateModule.set;
  14. var getInternalState = InternalStateModule.getterFor(ASYNC_FROM_SYNC_ITERATOR);
  15. var asyncFromSyncIteratorContinuation = function (result, resolve, reject) {
  16. var done = result.done;
  17. Promise.resolve(result.value).then(function (value) {
  18. resolve(createIterResultObject(value, done));
  19. }, reject);
  20. };
  21. var AsyncFromSyncIterator = function AsyncIterator(iterator) {
  22. setInternalState(this, {
  23. type: ASYNC_FROM_SYNC_ITERATOR,
  24. iterator: anObject(iterator),
  25. next: iterator.next
  26. });
  27. };
  28. AsyncFromSyncIterator.prototype = defineBuiltIns(create(AsyncIteratorPrototype), {
  29. next: function next() {
  30. var state = getInternalState(this);
  31. return new Promise(function (resolve, reject) {
  32. var result = anObject(call(state.next, state.iterator));
  33. asyncFromSyncIteratorContinuation(result, resolve, reject);
  34. });
  35. },
  36. 'return': function () {
  37. var iterator = getInternalState(this).iterator;
  38. return new Promise(function (resolve, reject) {
  39. var $return = getMethod(iterator, 'return');
  40. if ($return === undefined) return resolve(createIterResultObject(undefined, true));
  41. var result = anObject(call($return, iterator));
  42. asyncFromSyncIteratorContinuation(result, resolve, reject);
  43. });
  44. }
  45. });
  46. module.exports = AsyncFromSyncIterator;