CreateListFromArrayLike.js 1.2 KB

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  1. 'use strict';
  2. var $TypeError = require('es-errors/type');
  3. var isObject = require('es-object-atoms/isObject');
  4. var Get = require('./Get');
  5. var LengthOfArrayLike = require('./LengthOfArrayLike');
  6. var ToString = require('./ToString');
  7. var isPropertyKey = require('../helpers/isPropertyKey');
  8. // https://262.ecma-international.org/16.0/#sec-createlistfromarraylike
  9. module.exports = function CreateListFromArrayLike(obj) {
  10. var validElementTypes = arguments.length > 1
  11. ? arguments[1]
  12. : 'ALL'; // step 1
  13. if (validElementTypes !== 'ALL' && validElementTypes !== 'PROPERTY-KEY') {
  14. throw new $TypeError('Assertion failed: `validElementType` must be ~ALL~ or ~PROPERTY-KEY~');
  15. }
  16. if (!isObject(obj)) {
  17. throw new $TypeError('Assertion failed: `obj` must be an Object'); // step 2
  18. }
  19. var len = LengthOfArrayLike(obj); // step 3
  20. var list = []; // step 4
  21. var index = 0; // step 5
  22. while (index < len) { // step 6
  23. var indexName = ToString(index); // step 6.a
  24. var next = Get(obj, indexName); // step 6.b
  25. if (validElementTypes === 'PROPERTY-KEY' && !isPropertyKey(next)) {
  26. throw new $TypeError('item ' + indexName + ' is not a valid property key'); // step 6.c
  27. }
  28. list[list.length] = next; // step 6.d
  29. index += 1; // step 6.e
  30. }
  31. return list; // step 7
  32. };