function fetchSeries(series, start_date, end_date) {
let ids = series.map((d) => d.series_id).join(";");
return d3
.json(getQueryUrl(ids, start_date, end_date))
.then((response) =>
response.series
.flatMap((s) =>
s.data.map((d) => ({
id: s.series_id,
name: s.name,
date: parseDate(d[0]),
value: d[1]
}))
)
.sort((a, b) => +a.date - +b.date)
);
}