Function flushPendingAppends

src/core/createRenderCoordinator.ts:2069–2203

()

  };

  const flushPendingAppends = (): boolean => {
    if (pendingAppendByIndex.size === 0) return false;

    appendedGpuThisFrame.clear();

    const zoomRangeBefore = zoomState?.getRange() ?? null;
    const isFullSpanZoomBefore = isFullSpanZoomRange(zoomRangeBefore);
    const canAutoScroll =
      currentOptions.autoScroll === true &&
      zoomState != null &&
      currentOptions.xAxis.min == null &&
      currentOptions.xAxis.max == null;

    // Capture the pre-append visible domain so we can preserve it for “panned away” behavior.
    const prevBaseXDomain = computeBaseXDomain(currentOptions, runtimeRawBoundsByIndex);
    const prevVisibleXDomain = zoomRangeBefore ? computeVisibleXDomain(prevBaseXDomain, zoomRangeBefore) : null;

    let didAppendAny = false;

    for (const [seriesIndex, points] of pendingAppendByIndex) {
      if (points.length === 0) continue;
      const s = currentOptions.series[seriesIndex];
      if (!s || s.type === 'pie') continue;
      didAppendAny = true;

      if (s.type === 'candlestick') {
        // Handle candlestick OHLC data.
        let raw = runtimeRawDataByIndex[seriesIndex] as OHLCDataPoint[] | null;
        if (!raw) {
          const seed = (s.rawData ?? s.data) as ReadonlyArray<OHLCDataPoint>;
          raw = seed.length === 0 ? [] : seed.slice();
          runtimeRawDataByIndex[seriesIndex] = raw;
          runtimeRawBoundsByIndex[seriesIndex] = s.rawBounds ?? null;
        }

        const ohlcPoints = points as unknown as ReadonlyArray<OHLCDataPoint>;
        raw.push(...ohlcPoints);
        runtimeRawBoundsByIndex[seriesIndex] = extendBoundsWithOHLCDataPoints(
          runtimeRawBoundsByIndex[seriesIndex],
          ohlcPoints
        );
      } else {
        // Handle other cartesian series (line, area, bar, scatter).
        let raw = runtimeRawDataByIndex[seriesIndex] as DataPoint[] | null;
        if (!raw) {
          const seed = (s.rawData ?? s.data) as ReadonlyArray<DataPoint>;
          raw = seed.length === 0 ? [] : seed.slice();
          runtimeRawDataByIndex[seriesIndex] = raw;
          runtimeRawBoundsByIndex[seriesIndex] = s.rawBounds ?? computeRawBoundsFromData(raw);
        }

        const dataPoints = points as unknown as ReadonlyArray<DataPoint>;
        
        // Optional fast-path: if the GPU buffer currently represents the full, unsampled line series,
        // we can append just the new points to the existing GPU buffer (no full re-upload).
        if (
          s.type === 'line' &&
          s.sampling === 'none' &&