esnext.iterator.zip.js 3.0 KB

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  1. 'use strict';
  2. var $ = require('../internals/export');
  3. var anObject = require('../internals/an-object');
  4. var anObjectOrUndefined = require('../internals/an-object-or-undefined');
  5. var call = require('../internals/function-call');
  6. var uncurryThis = require('../internals/function-uncurry-this');
  7. var getIteratorRecord = require('../internals/get-iterator-record');
  8. var getIteratorFlattenable = require('../internals/get-iterator-flattenable');
  9. var getModeOption = require('../internals/get-mode-option');
  10. var iteratorClose = require('../internals/iterator-close');
  11. var iteratorCloseAll = require('../internals/iterator-close-all');
  12. var iteratorZip = require('../internals/iterator-zip');
  13. var IS_PURE = require('../internals/is-pure');
  14. var concat = uncurryThis([].concat);
  15. var push = uncurryThis([].push);
  16. var THROW = 'throw';
  17. // `Iterator.zip` method
  18. // https://github.com/tc39/proposal-joint-iteration
  19. $({ target: 'Iterator', stat: true, forced: IS_PURE }, {
  20. zip: function zip(iterables /* , options */) {
  21. anObject(iterables);
  22. var options = arguments.length > 1 ? anObjectOrUndefined(arguments[1]) : undefined;
  23. var mode = getModeOption(options);
  24. var paddingOption = mode === 'longest' ? anObjectOrUndefined(options && options.padding) : undefined;
  25. var iters = [];
  26. var padding = [];
  27. var inputIter = getIteratorRecord(iterables);
  28. var iter, done, next;
  29. while (!done) {
  30. try {
  31. next = anObject(call(inputIter.next, inputIter.iterator));
  32. done = next.done;
  33. } catch (error) {
  34. return iteratorCloseAll(iters, THROW, error);
  35. }
  36. if (!done) {
  37. try {
  38. iter = getIteratorFlattenable(next.value, false);
  39. } catch (error) {
  40. return iteratorCloseAll(concat([inputIter], iters), THROW, error);
  41. }
  42. push(iters, iter);
  43. }
  44. }
  45. var iterCount = iters.length;
  46. var i, paddingDone, paddingIter;
  47. if (mode === 'longest') {
  48. if (paddingOption === undefined) {
  49. for (i = 0; i < iterCount; i++) push(padding, undefined);
  50. } else {
  51. try {
  52. paddingIter = getIteratorRecord(paddingOption);
  53. } catch (error) {
  54. return iteratorCloseAll(iters, THROW, error);
  55. }
  56. var usingIterator = true;
  57. for (i = 0; i < iterCount; i++) {
  58. if (usingIterator) {
  59. try {
  60. next = anObject(call(paddingIter.next, paddingIter.iterator));
  61. paddingDone = next.done;
  62. next = next.value;
  63. } catch (error) {
  64. return iteratorCloseAll(iters, THROW, error);
  65. }
  66. if (paddingDone) {
  67. usingIterator = false;
  68. } else {
  69. push(padding, next);
  70. }
  71. } else {
  72. push(padding, undefined);
  73. }
  74. }
  75. if (usingIterator) {
  76. try {
  77. iteratorClose(paddingIter.iterator, 'normal');
  78. } catch (error) {
  79. return iteratorCloseAll(iters, THROW, error);
  80. }
  81. }
  82. }
  83. }
  84. return iteratorZip(iters, mode, padding);
  85. }
  86. });