index.js 1.3 KB

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  1. 'use strict';
  2. var SLOT = require('internal-slot');
  3. var $SyntaxError = require('es-errors/syntax');
  4. var $StopIteration = typeof StopIteration === 'object' ? StopIteration : null;
  5. /** @type {import('.')} */
  6. module.exports = function getStopIterationIterator(origIterator) {
  7. if (!$StopIteration) {
  8. throw new $SyntaxError('this environment lacks StopIteration');
  9. }
  10. SLOT.set(origIterator, '[[Done]]', false);
  11. /** @template T @typedef {T extends Iterator<infer U> ? U : never} IteratorType */
  12. /** @typedef {IteratorType<ReturnType<typeof getStopIterationIterator>>} T */
  13. var siIterator = {
  14. next: /** @type {() => IteratorResult<T>} */ function next() {
  15. // eslint-disable-next-line no-extra-parens
  16. var iterator = /** @type {typeof origIterator} */ (SLOT.get(this, '[[Iterator]]'));
  17. var done = !!SLOT.get(iterator, '[[Done]]');
  18. try {
  19. return {
  20. done: done,
  21. // eslint-disable-next-line no-extra-parens
  22. value: done ? void undefined : /** @type {T} */ (iterator.next())
  23. };
  24. } catch (e) {
  25. SLOT.set(iterator, '[[Done]]', true);
  26. if (e !== $StopIteration) {
  27. throw e;
  28. }
  29. return {
  30. done: true,
  31. value: void undefined
  32. };
  33. }
  34. }
  35. };
  36. SLOT.set(siIterator, '[[Iterator]]', origIterator);
  37. // @ts-expect-error TODO FIXME
  38. return siIterator;
  39. };