array-includes.js 1.3 KB

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  1. 'use strict';
  2. var toIndexedObject = require('../internals/to-indexed-object');
  3. var toAbsoluteIndex = require('../internals/to-absolute-index');
  4. var lengthOfArrayLike = require('../internals/length-of-array-like');
  5. // `Array.prototype.{ indexOf, includes }` methods implementation
  6. var createMethod = function (IS_INCLUDES) {
  7. return function ($this, el, fromIndex) {
  8. var O = toIndexedObject($this);
  9. var length = lengthOfArrayLike(O);
  10. var index = toAbsoluteIndex(fromIndex, length);
  11. var value;
  12. // Array#includes uses SameValueZero equality algorithm
  13. // eslint-disable-next-line no-self-compare -- NaN check
  14. if (IS_INCLUDES && el !== el) while (length > index) {
  15. value = O[index++];
  16. // eslint-disable-next-line no-self-compare -- NaN check
  17. if (value !== value) return true;
  18. // Array#indexOf ignores holes, Array#includes - not
  19. } else for (;length > index; index++) {
  20. if ((IS_INCLUDES || index in O) && O[index] === el) return IS_INCLUDES || index || 0;
  21. } return !IS_INCLUDES && -1;
  22. };
  23. };
  24. module.exports = {
  25. // `Array.prototype.includes` method
  26. // https://tc39.es/ecma262/#sec-array.prototype.includes
  27. includes: createMethod(true),
  28. // `Array.prototype.indexOf` method
  29. // https://tc39.es/ecma262/#sec-array.prototype.indexof
  30. indexOf: createMethod(false)
  31. };