esnext.iterator.take.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 call = require('../internals/function-call');
  5. var anObject = require('../internals/an-object');
  6. var getIteratorDirect = require('../internals/get-iterator-direct');
  7. var notANaN = require('../internals/not-a-nan');
  8. var toPositiveInteger = require('../internals/to-positive-integer');
  9. var createIteratorProxy = require('../internals/iterator-create-proxy');
  10. var iteratorClose = require('../internals/iterator-close');
  11. var IteratorProxy = createIteratorProxy(function () {
  12. var iterator = this.iterator;
  13. if (!this.remaining--) {
  14. this.done = true;
  15. return iteratorClose(iterator, 'normal', undefined);
  16. }
  17. var result = anObject(call(this.next, iterator));
  18. var done = this.done = !!result.done;
  19. if (!done) return result.value;
  20. });
  21. $({ target: 'Iterator', proto: true, real: true, forced: true }, {
  22. take: function take(limit) {
  23. return new IteratorProxy(getIteratorDirect(this), {
  24. remaining: toPositiveInteger(notANaN(+limit))
  25. });
  26. }
  27. });