| | |
| | | 'use strict'; |
| | | // TODO: Remove from `core-js@4` |
| | | var $ = require('../internals/export'); |
| | | var charAt = require('../internals/string-multibyte').charAt; |
| | | var fails = require('../internals/fails'); |
| | | |
| | | var FORCED = fails(function () { |
| | | return '𠮷'.at(0) !== '𠮷'; |
| | | }); |
| | | var requireObjectCoercible = require('../internals/require-object-coercible'); |
| | | var toIntegerOrInfinity = require('../internals/to-integer-or-infinity'); |
| | | var toString = require('../internals/to-string'); |
| | | |
| | | // `String.prototype.at` method |
| | | // https://github.com/mathiasbynens/String.prototype.at |
| | | $({ target: 'String', proto: true, forced: FORCED }, { |
| | | at: function at(pos) { |
| | | return charAt(this, pos); |
| | | $({ target: 'String', proto: true, forced: true }, { |
| | | at: function at(index) { |
| | | var S = toString(requireObjectCoercible(this)); |
| | | var len = S.length; |
| | | var relativeIndex = toIntegerOrInfinity(index); |
| | | var k = relativeIndex >= 0 ? relativeIndex : len + relativeIndex; |
| | | return (k < 0 || k >= len) ? undefined : charAt(S, k); |
| | | } |
| | | }); |