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// Based on: https://github.com/mathiasbynens/String.prototype.codePointAt
// Thanks @mathiasbynens !
'use strict';
var toInteger = require('../../../number/to-integer')
, validValue = require('../../../object/valid-value');
module.exports = function (pos) {
var str = String(validValue(this)), l = str.length, first, second;
pos = toInteger(pos);
// Account for out-of-bounds indices:
if (pos < 0 || pos >= l) return undefined;
// Get the first code unit
first = str.charCodeAt(pos);
if ((first >= 0xD800) && (first <= 0xDBFF) && (l > pos + 1)) {
second = str.charCodeAt(pos + 1);
if (second >= 0xDC00 && second <= 0xDFFF) {
// http://mathiasbynens.be/notes/javascript-encoding#surrogate-formulae
return (first - 0xD800) * 0x400 + second - 0xDC00 + 0x10000;
}
}
return first;
};
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