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/*! https://mths.be/codepointat v1.0.0 by @mathias */
'use strict';
var callBound = require('es-abstract/helpers/callBound');
var RequireObjectCoercible = require('es-abstract/2019/RequireObjectCoercible');
var ToString = require('es-abstract/2019/ToString');
var ToInteger = require('es-abstract/2019/ToInteger');
var StringCharCodeAt = callBound('String.prototype.charCodeAt');
module.exports = function codePointAt(position) {
var O = RequireObjectCoercible(this);
var string = ToString(O);
var size = string.length;
var index = ToInteger(position);
// Account for out-of-bounds indices:
if (index < 0 || index >= size) {
return undefined;
}
// Get the first code unit
var first = StringCharCodeAt(string, index);
var second;
if ( // check if it’s the start of a surrogate pair
first >= 0xD800 && first <= 0xDBFF && // high surrogate
size > index + 1 // there is a next code unit
) {
second = StringCharCodeAt(string, index + 1);
if (second >= 0xDC00 && second <= 0xDFFF) { // low surrogate
// https://mathiasbynens.be/notes/javascript-encoding#surrogate-formulae
return (first - 0xD800) * 0x400 + second - 0xDC00 + 0x10000;
}
}
return first;
};
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