sharkdest

...
render() {
 let keys = {};
 rows.map(row => {
    keys.key = row.number;
 });

 return (
 ...
                <CSVLink
                  key={keys.key}
                  className="btn btn-secondary btn-download"
                  data={rows}
                  separator={";"}
                  filename="netpositions.csv"
                >
                  <span className="oi oi-data-transfer-download" />
                </CSVLink>
 ))}
...
 )
}