CreateIteratorFromClosure.js 2.0 KB

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  1. 'use strict';
  2. var $TypeError = require('es-errors/type');
  3. var GeneratorStart = require('./GeneratorStart');
  4. var IsArray = require('./IsArray');
  5. var IsCallable = require('./IsCallable');
  6. var OrdinaryObjectCreate = require('./OrdinaryObjectCreate');
  7. var every = require('../helpers/every');
  8. var SLOT = require('internal-slot');
  9. var safeConcat = require('safe-array-concat');
  10. var isObject = require('es-object-atoms/isObject');
  11. var isString = function isString(slot) {
  12. return typeof slot === 'string';
  13. };
  14. // https://262.ecma-international.org/16.0/#sec-createiteratorfromclosure
  15. module.exports = function CreateIteratorFromClosure(closure, generatorBrand, generatorPrototype) {
  16. if (!IsCallable(closure)) {
  17. throw new $TypeError('`closure` must be a function');
  18. }
  19. if (typeof generatorBrand !== 'string') {
  20. throw new $TypeError('`generatorBrand` must be a string');
  21. }
  22. if (!isObject(generatorPrototype)) {
  23. throw new $TypeError('`generatorPrototype` must be an object');
  24. }
  25. var extraSlots = arguments.length > 3 ? arguments[3] : []; // step 2
  26. if (arguments.length > 3) {
  27. if (!IsArray(extraSlots) || !every(extraSlots, isString)) {
  28. throw new $TypeError('`extraSlots` must be a List of String internal slot names');
  29. }
  30. }
  31. var internalSlotsList = safeConcat(extraSlots, ['[[GeneratorContext]]', '[[GeneratorBrand]]', '[[GeneratorState]]']); // step 3
  32. var generator = OrdinaryObjectCreate(generatorPrototype, internalSlotsList); // steps 4, 6
  33. SLOT.set(generator, '[[GeneratorBrand]]', generatorBrand); // step 5
  34. SLOT.set(generator, '[[GeneratorState]]', 'SUSPENDED-START'); // step 6
  35. SLOT.assert(closure, '[[Sentinel]]'); // our userland slot
  36. SLOT.set(generator, '[[Sentinel]]', SLOT.get(closure, '[[Sentinel]]')); // our userland slot
  37. SLOT.assert(closure, '[[CloseIfAbrupt]]'); // our second userland slot
  38. SLOT.set(generator, '[[CloseIfAbrupt]]', SLOT.get(closure, '[[CloseIfAbrupt]]')); // our second userland slot
  39. GeneratorStart(generator, closure); // step 14
  40. return generator; // step 16
  41. };