async-iterator-iteration.js 3.7 KB

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  1. 'use strict';
  2. // https://github.com/tc39/proposal-async-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 isObject = require('../internals/is-object');
  8. var doesNotExceedSafeInteger = require('../internals/does-not-exceed-safe-integer');
  9. var getBuiltIn = require('../internals/get-built-in');
  10. var createProperty = require('../internals/create-property');
  11. var setArrayLength = require('../internals/array-set-length');
  12. var getIteratorDirect = require('../internals/get-iterator-direct');
  13. var closeAsyncIteration = require('../internals/async-iterator-close');
  14. var createMethod = function (TYPE) {
  15. var IS_TO_ARRAY = TYPE === 0;
  16. var IS_FOR_EACH = TYPE === 1;
  17. var IS_EVERY = TYPE === 2;
  18. var IS_SOME = TYPE === 3;
  19. return function (object, fn, target) {
  20. anObject(object);
  21. var MAPPING = fn !== undefined;
  22. if (MAPPING || !IS_TO_ARRAY) aCallable(fn);
  23. var record = getIteratorDirect(object);
  24. var Promise = getBuiltIn('Promise');
  25. var iterator = record.iterator;
  26. var next = record.next;
  27. var counter = 0;
  28. return new Promise(function (resolve, reject) {
  29. var ifAbruptCloseAsyncIterator = function (error) {
  30. closeAsyncIteration(iterator, reject, error, reject);
  31. };
  32. var loop = function () {
  33. try {
  34. try {
  35. doesNotExceedSafeInteger(counter);
  36. } catch (error5) {
  37. return ifAbruptCloseAsyncIterator(error5);
  38. }
  39. Promise.resolve(anObject(call(next, iterator))).then(function (step) {
  40. try {
  41. if (anObject(step).done) {
  42. if (IS_TO_ARRAY) {
  43. setArrayLength(target, counter);
  44. resolve(target);
  45. } else resolve(IS_SOME ? false : IS_EVERY || undefined);
  46. } else {
  47. var value = step.value;
  48. try {
  49. if (MAPPING) {
  50. var index = counter++;
  51. var result = fn(value, index);
  52. var handler = function ($result) {
  53. if (IS_FOR_EACH) {
  54. loop();
  55. } else if (IS_EVERY) {
  56. $result ? loop() : closeAsyncIteration(iterator, resolve, false, reject);
  57. } else if (IS_TO_ARRAY) {
  58. try {
  59. createProperty(target, index, $result);
  60. loop();
  61. } catch (error4) { ifAbruptCloseAsyncIterator(error4); }
  62. } else {
  63. $result ? closeAsyncIteration(iterator, resolve, IS_SOME || value, reject) : loop();
  64. }
  65. };
  66. if (isObject(result)) Promise.resolve(result).then(handler, ifAbruptCloseAsyncIterator);
  67. else handler(result);
  68. } else {
  69. createProperty(target, counter++, value);
  70. loop();
  71. }
  72. } catch (error3) { ifAbruptCloseAsyncIterator(error3); }
  73. }
  74. } catch (error2) { reject(error2); }
  75. }, reject);
  76. } catch (error) { reject(error); }
  77. };
  78. loop();
  79. });
  80. };
  81. };
  82. module.exports = {
  83. // `AsyncIterator.prototype.toArray` / `Array.fromAsync` methods
  84. toArray: createMethod(0),
  85. // `AsyncIterator.prototype.forEach` method
  86. forEach: createMethod(1),
  87. // `AsyncIterator.prototype.every` method
  88. every: createMethod(2),
  89. // `AsyncIterator.prototype.some` method
  90. some: createMethod(3),
  91. // `AsyncIterator.prototype.find` method
  92. find: createMethod(4)
  93. };