async-iterator-iteration.js 3.1 KB

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  1. 'use strict';
  2. // https://github.com/tc39/proposal-iterator-helpers
  3. // https://github.com/tc39/proposal-array-from-async
  4. var call = require('../internals/function-call');
  5. var aCallable = require('../internals/a-callable');
  6. var anObject = require('../internals/an-object');
  7. var doesNotExceedSafeInteger = require('../internals/does-not-exceed-safe-integer');
  8. var getBuiltIn = require('../internals/get-built-in');
  9. var getIteratorDirect = require('../internals/get-iterator-direct');
  10. var closeAsyncIteration = require('../internals/async-iterator-close');
  11. var createMethod = function (TYPE) {
  12. var IS_TO_ARRAY = TYPE == 0;
  13. var IS_FOR_EACH = TYPE == 1;
  14. var IS_EVERY = TYPE == 2;
  15. var IS_SOME = TYPE == 3;
  16. return function (object, fn, target) {
  17. var record = getIteratorDirect(object);
  18. var Promise = getBuiltIn('Promise');
  19. var iterator = record.iterator;
  20. var next = record.next;
  21. var index = 0;
  22. var MAPPING = fn !== undefined;
  23. if (MAPPING || !IS_TO_ARRAY) aCallable(fn);
  24. return new Promise(function (resolve, reject) {
  25. var ifAbruptCloseAsyncIterator = function (error) {
  26. closeAsyncIteration(iterator, reject, error, reject);
  27. };
  28. var loop = function () {
  29. try {
  30. if (IS_TO_ARRAY && MAPPING) try {
  31. doesNotExceedSafeInteger(index);
  32. } catch (error5) { ifAbruptCloseAsyncIterator(error5); }
  33. Promise.resolve(anObject(call(next, iterator))).then(function (step) {
  34. try {
  35. if (anObject(step).done) {
  36. if (IS_TO_ARRAY) {
  37. target.length = index;
  38. resolve(target);
  39. } else resolve(IS_SOME ? false : IS_EVERY || undefined);
  40. } else {
  41. var value = step.value;
  42. try {
  43. if (MAPPING) {
  44. Promise.resolve(IS_TO_ARRAY ? fn(value, index) : fn(value)).then(function (result) {
  45. if (IS_FOR_EACH) {
  46. loop();
  47. } else if (IS_EVERY) {
  48. result ? loop() : closeAsyncIteration(iterator, resolve, false, reject);
  49. } else if (IS_TO_ARRAY) {
  50. try {
  51. target[index++] = result;
  52. loop();
  53. } catch (error4) { ifAbruptCloseAsyncIterator(error4); }
  54. } else {
  55. result ? closeAsyncIteration(iterator, resolve, IS_SOME || value, reject) : loop();
  56. }
  57. }, ifAbruptCloseAsyncIterator);
  58. } else {
  59. target[index++] = value;
  60. loop();
  61. }
  62. } catch (error3) { ifAbruptCloseAsyncIterator(error3); }
  63. }
  64. } catch (error2) { reject(error2); }
  65. }, reject);
  66. } catch (error) { reject(error); }
  67. };
  68. loop();
  69. });
  70. };
  71. };
  72. module.exports = {
  73. toArray: createMethod(0),
  74. forEach: createMethod(1),
  75. every: createMethod(2),
  76. some: createMethod(3),
  77. find: createMethod(4)
  78. };