Function findVisibleRangeIndicesByX

src/core/createRenderCoordinator.ts:793–820

(
  data: ReadonlyArray<DataPoint>,
  xMin: number,
  xMax: number
)

};

const findVisibleRangeIndicesByX = (
  data: ReadonlyArray<DataPoint>,
  xMin: number,
  xMax: number
): { readonly start: number; readonly end: number } => {
  const n = data.length;
  if (n === 0) return { start: 0, end: 0 };
  if (!Number.isFinite(xMin) || !Number.isFinite(xMax)) return { start: 0, end: n };

  const isTuple = isTupleDataArray(data);
  const canBinarySearch = isMonotonicNonDecreasingFiniteX(data, isTuple);
  if (!canBinarySearch) {
    // Data is not monotonic by x; we can't represent the visible set as a contiguous index range.
    // Fall back to processing the full series for correctness.
    return { start: 0, end: n };
  }

  const start = isTuple
    ? lowerBoundXTuple(data as ReadonlyArray<TuplePoint>, xMin)
    : lowerBoundXObject(data as ReadonlyArray<ObjectPoint>, xMin);
  const end = isTuple
    ? upperBoundXTuple(data as ReadonlyArray<TuplePoint>, xMax)
    : upperBoundXObject(data as ReadonlyArray<ObjectPoint>, xMax);

  const s = clampInt(start, 0, n);
  const e = clampInt(end, 0, n);
  return e <= s ? { start: s, end: s } : { start: s, end: e };
};

function isTupleOHLCDataPoint(p: OHLCDataPoint): p is OHLCDataPointTuple {
  return Array.isArray(p);