Function interpolate

src/scales/scale.timeseries.js:12–32

* Linearly interpolates the given source `val` using the table. If value is out of bounds, values * at edges are used for the interpolation. * @param {object} table * @param {number} val * @param {boolean} [reverse] lookup time based on position instead of vice versa * @return {object}

(table, val, reverse)

 * @return {object}
 */
function interpolate(table, val, reverse) {
  let lo = 0;
  let hi = table.length - 1;
  let prevSource, nextSource, prevTarget, nextTarget;
  if (reverse) {
    if (val >= table[lo].pos && val <= table[hi].pos) {
      ({lo, hi} = _lookupByKey(table, 'pos', val));
    }
    ({pos: prevSource, time: prevTarget} = table[lo]);
    ({pos: nextSource, time: nextTarget} = table[hi]);
  } else {
    if (val >= table[lo].time && val <= table[hi].time) {
      ({lo, hi} = _lookupByKey(table, 'time', val));
    }
    ({time: prevSource, pos: prevTarget} = table[lo]);
    ({time: nextSource, pos: nextTarget} = table[hi]);
  }

  const span = nextSource - prevSource;
  return span ? prevTarget + (nextTarget - prevTarget) * (val - prevSource) / span : prevTarget;
}

class TimeSeriesScale extends TimeScale {