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- 'use strict';
- var $TypeError = require('es-errors/type');
- var callBound = require('call-bound');
- var $charAt = callBound('String.prototype.charAt');
- var $stringToString = callBound('String.prototype.toString');
- var CanonicalNumericIndexString = require('./CanonicalNumericIndexString');
- var IsInteger = require('./IsInteger');
- var isObject = require('../helpers/isObject');
- var isPropertyKey = require('../helpers/isPropertyKey');
- var isNegativeZero = require('math-intrinsics/isNegativeZero');
- // https://262.ecma-international.org/8.0/#sec-stringgetownproperty
- module.exports = function StringGetOwnProperty(S, P) {
- var str;
- if (isObject(S)) {
- try {
- str = $stringToString(S);
- } catch (e) { /**/ }
- }
- if (typeof str !== 'string') {
- throw new $TypeError('Assertion failed: `S` must be a boxed string object');
- }
- if (!isPropertyKey(P)) {
- throw new $TypeError('Assertion failed: P is not a Property Key');
- }
- if (typeof P !== 'string') {
- return void undefined;
- }
- var index = CanonicalNumericIndexString(P);
- var len = str.length;
- if (typeof index === 'undefined' || !IsInteger(index) || isNegativeZero(index) || index < 0 || len <= index) {
- return void undefined;
- }
- var resultStr = $charAt(S, index);
- return {
- '[[Configurable]]': false,
- '[[Enumerable]]': true,
- '[[Value]]': resultStr,
- '[[Writable]]': false
- };
- };
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