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// 22.1.3.3 Array.prototype.copyWithin(target, start, end = this.length)
'use strict';
var toObject = require('./_to-object')
, toIndex = require('./_to-index')
, toLength = require('./_to-length');
module.exports = [].copyWithin || function copyWithin(target/*= 0*/, start/*= 0, end = @length*/){
var O = toObject(this)
, len = toLength(O.length)
, to = toIndex(target, len)
, from = toIndex(start, len)
, end = arguments.length > 2 ? arguments[2] : undefined
, count = Math.min((end === undefined ? len : toIndex(end, len)) - from, len - to)
, inc = 1;
if(from < to && to < from + count){
inc = -1;
from += count - 1;
to += count - 1;
}
while(count-- > 0){
if(from in O)O[to] = O[from];
else delete O[to];
to += inc;
from += inc;
} return O;
};
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