gristlabs_grist-core/app/client/lib/chartUtil.ts

import {typedCompare} from 'app/common/SortFunc';
import {Datum} from 'plotly.js';

/**
 * Sort all values in a list of series according to the values in the first one.
 */
export function sortByXValues(series: Array<{values: Datum[]}>): void {
  // The order of points matters for graph types that connect points with lines: the lines are
  // drawn in order in which the points appear in the data. For the chart types we support, it
  // only makes sense to keep the points sorted. (The only downside is that Grist line charts can
  // no longer produce arbitrary line drawings.)
  if (!series[0]) { return; }
  const xValues = series[0].values;
  const indices = xValues.map((val, i) => i);
  indices.sort((a, b) => typedCompare(xValues[a], xValues[b]));
  for (const s of series) {
    const values = s.values;
    s.values = indices.map((i) => values[i]);
  }
}