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var uncurryThis = require('../internals/function-uncurry-this');
var toIntegerOrInfinity = require('../internals/to-integer-or-infinity');
var toString = require('../internals/to-string');
var requireObjectCoercible = require('../internals/require-object-coercible');
var charAt = uncurryThis(''.charAt);
var charCodeAt = uncurryThis(''.charCodeAt);
var stringSlice = uncurryThis(''.slice);
var createMethod = function (CONVERT_TO_STRING) {
return function ($this, pos) {
var S = toString(requireObjectCoercible($this));
var position = toIntegerOrInfinity(pos);
var size = S.length;
var first, second;
if (position < 0 || position >= size) return CONVERT_TO_STRING ? '' : undefined;
first = charCodeAt(S, position);
return first < 0xD800 || first > 0xDBFF || position + 1 === size
|| (second = charCodeAt(S, position + 1)) < 0xDC00 || second > 0xDFFF
? CONVERT_TO_STRING
? charAt(S, position)
: first
: CONVERT_TO_STRING
? stringSlice(S, position, position + 2)
: (first - 0xD800 << 10) + (second - 0xDC00) + 0x10000;
};
};
module.exports = {
// `String.prototype.codePointAt` method
// https://tc39.es/ecma262/#sec-string.prototype.codepointat
codeAt: createMethod(false),
// `String.prototype.at` method
// https://github.com/mathiasbynens/String.prototype.at
charAt: createMethod(true)
};