esnext.async-iterator.map.js 1.1 KB

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  1. 'use strict';
  2. // https://github.com/tc39/proposal-iterator-helpers
  3. var $ = require('../internals/export');
  4. var apply = require('../internals/function-apply');
  5. var aCallable = require('../internals/a-callable');
  6. var anObject = require('../internals/an-object');
  7. var getIteratorDirect = require('../internals/get-iterator-direct');
  8. var createAsyncIteratorProxy = require('../internals/async-iterator-create-proxy');
  9. var AsyncIteratorProxy = createAsyncIteratorProxy(function (Promise, args) {
  10. var state = this;
  11. var mapper = state.mapper;
  12. return Promise.resolve(anObject(apply(state.next, state.iterator, args))).then(function (step) {
  13. if (anObject(step).done) {
  14. state.done = true;
  15. return { done: true, value: undefined };
  16. }
  17. return Promise.resolve(mapper(step.value)).then(function (value) {
  18. return { done: false, value: value };
  19. });
  20. });
  21. });
  22. $({ target: 'AsyncIterator', proto: true, real: true, forced: true }, {
  23. map: function map(mapper) {
  24. return new AsyncIteratorProxy(getIteratorDirect(this), {
  25. mapper: aCallable(mapper)
  26. });
  27. }
  28. });