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// Based on: https://github.com/mathiasbynens/String.prototype.at
// Thanks @mathiasbynens !
"use strict" ;
var toInteger = require ( "../../number/to-integer" )
, validValue = require ( "../../object/valid-value" ) ;
module . exports = function ( pos ) {
var str = String ( validValue ( this ) ) , size = str . length , cuFirst , cuSecond , nextPos , len ;
pos = toInteger ( pos ) ;
// Account for out-of-bounds indices
// The odd lower bound is because the ToInteger operation is
// going to round `n` to `0` for `-1 < n <= 0`.
if ( pos <= - 1 || pos >= size ) return "" ;
// Second half of `ToInteger`
// eslint-disable-next-line no-bitwise
pos |= 0 ;
// Get the first code unit and code unit value
cuFirst = str . charCodeAt ( pos ) ;
nextPos = pos + 1 ;
len = 1 ;
if (
// Check if it’
cuFirst >= 0xd800 &&
cuFirst <= 0xdbff && // High surrogate
size > nextPos // There is a next code unit
) {
cuSecond = str . charCodeAt ( nextPos ) ;
if ( cuSecond >= 0xdc00 && cuSecond <= 0xdfff ) len = 2 ; // Low surrogate
}
return str . slice ( pos , pos + len ) ;
} ;
