source: imaps-frontend/node_modules/es-abstract/2017/StringGetOwnProperty.js@ d565449

'use strict';

var $TypeError = require('es-errors/type');

var callBound = require('call-bind/callBound');
var $charAt = callBound('String.prototype.charAt');
var $stringToString = callBound('String.prototype.toString');

var CanonicalNumericIndexString = require('./CanonicalNumericIndexString');
var IsInteger = require('./IsInteger');
var IsPropertyKey = require('./IsPropertyKey');
var Type = require('./Type');

var isNegativeZero = require('is-negative-zero');

// https://262.ecma-international.org/8.0/#sec-stringgetownproperty

module.exports = function StringGetOwnProperty(S, P) {
        var str;
        if (Type(S) === 'Object') {
                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: IsPropertyKey(P) is not true');
        }
        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
        };
};