GeneratorStart.js 1.5 KB

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  1. 'use strict';
  2. var $TypeError = require('es-errors/type');
  3. var CreateIterResultObject = require('es-abstract/2024/CreateIterResultObject');
  4. var IsCallable = require('es-abstract/2024/IsCallable');
  5. var Type = require('es-abstract/2024/Type');
  6. var SLOT = require('internal-slot');
  7. module.exports = function GeneratorStart(generator, closure) {
  8. SLOT.assert(generator, '[[GeneratorState]]');
  9. SLOT.assert(generator, '[[GeneratorContext]]');
  10. SLOT.assert(generator, '[[GeneratorBrand]]');
  11. SLOT.assert(generator, '[[Sentinel]]'); // our userland slot
  12. SLOT.assert(generator, '[[CloseIfAbrupt]]'); // our second userland slot
  13. if (!IsCallable(closure) || closure.length !== 0) {
  14. throw new $TypeError('`closure` must be a function that takes no arguments');
  15. }
  16. var sentinel = SLOT.get(closure, '[[Sentinel]]');
  17. if (Type(sentinel) !== 'Object') {
  18. throw new $TypeError('`closure.[[Sentinel]]` must be an object');
  19. }
  20. SLOT.set(generator, '[[GeneratorContext]]', function () { // steps 2-5
  21. try {
  22. var result = closure();
  23. if (result === sentinel) {
  24. SLOT.set(generator, '[[GeneratorState]]', 'completed');
  25. SLOT.set(generator, '[[GeneratorContext]]', null);
  26. return CreateIterResultObject(void undefined, true);
  27. }
  28. SLOT.set(generator, '[[GeneratorState]]', 'suspendedYield');
  29. return CreateIterResultObject(result, false);
  30. } catch (e) {
  31. SLOT.set(generator, '[[GeneratorState]]', 'completed');
  32. SLOT.set(generator, '[[GeneratorContext]]', null);
  33. throw e;
  34. }
  35. });
  36. SLOT.set(generator, '[[GeneratorState]]', 'suspendedStart'); // step 6
  37. };