| Leo Repp | 58b9f11 | 2021-11-22 11:57:47 +0100 | [diff] [blame^] | 1 | 'use strict'; |
| 2 | |
| 3 | var GetIntrinsic = require('get-intrinsic'); |
| 4 | |
| 5 | var $TypeError = GetIntrinsic('%TypeError%'); |
| 6 | |
| 7 | var callBound = require('call-bind/callBound'); |
| 8 | var $charAt = callBound('String.prototype.charAt'); |
| 9 | var $stringToString = callBound('String.prototype.toString'); |
| 10 | |
| 11 | var CanonicalNumericIndexString = require('./CanonicalNumericIndexString'); |
| 12 | var IsInteger = require('./IsInteger'); |
| 13 | var IsPropertyKey = require('./IsPropertyKey'); |
| 14 | var Type = require('./Type'); |
| 15 | |
| 16 | var isNegativeZero = require('is-negative-zero'); |
| 17 | |
| 18 | // https://262.ecma-international.org/8.0/#sec-stringgetownproperty |
| 19 | |
| 20 | module.exports = function StringGetOwnProperty(S, P) { |
| 21 | var str; |
| 22 | if (Type(S) === 'Object') { |
| 23 | try { |
| 24 | str = $stringToString(S); |
| 25 | } catch (e) { /**/ } |
| 26 | } |
| 27 | if (Type(str) !== 'String') { |
| 28 | throw new $TypeError('Assertion failed: `S` must be a boxed string object'); |
| 29 | } |
| 30 | if (!IsPropertyKey(P)) { |
| 31 | throw new $TypeError('Assertion failed: IsPropertyKey(P) is not true'); |
| 32 | } |
| 33 | if (Type(P) !== 'String') { |
| 34 | return void undefined; |
| 35 | } |
| 36 | var index = CanonicalNumericIndexString(P); |
| 37 | var len = str.length; |
| 38 | if (typeof index === 'undefined' || !IsInteger(index) || isNegativeZero(index) || index < 0 || len <= index) { |
| 39 | return void undefined; |
| 40 | } |
| 41 | var resultStr = $charAt(S, index); |
| 42 | return { |
| 43 | '[[Configurable]]': false, |
| 44 | '[[Enumerable]]': true, |
| 45 | '[[Value]]': resultStr, |
| 46 | '[[Writable]]': false |
| 47 | }; |
| 48 | }; |