function drawLine()

in src/Wlinescatter/index.tsx [378:469]
77 lines of code
20 McCabe index (conditional complexity)

function drawLine(chart: View, config: WlinescatterConfig, yAxisKey = 'y', legendKey = 'type') {
  let areaColors = config.areaColors || config.lineColors;
  if (Array.isArray(config.lineColors) && Array.isArray(config.areaColors)) {
    areaColors = mergeArray([], config.lineColors, config.areaColors);
  }

  if (Array.isArray(areaColors)) {
    areaColors = getAreaColors(areaColors);
  }

  let lineGeom = null;
  let areaGeom = null;
  const { lineWidth } = config;

  // 区域、堆叠、平滑曲线
  const lineShape = config.spline ? 'smooth' : 'line';
  const areaShape = config.spline ? 'smooth' : 'area';

  const stack = config.stack;

  if (config.area && stack) {
    areaGeom = chart.area()
      .position(['x', yAxisKey])
      .color(legendKey, areaColors)
      .tooltip(false)
      .shape(areaShape)
      .adjust('stack');
    lineGeom = chart.line()
      .position(['x', yAxisKey])
      .color(legendKey, config.lineColors)
      .shape(lineShape)
      .adjust('stack');
  } else if (config.area && !stack) {
    areaGeom = chart.area()
      .position(['x', yAxisKey])
      .color(legendKey, areaColors)
      .tooltip(false)
      .shape(areaShape)
    lineGeom = chart.line()
      .position(['x', yAxisKey])
      .color(legendKey, config.lineColors)
      .shape(lineShape);
  } else {
    lineGeom = chart.line()
      .position(['x', yAxisKey])
      .color(legendKey, config.lineColors)
      .shape(lineShape);
  }

  if (areaGeom && typeof config.area === 'object') {
    if (config.area.geomStyle) {
      geomStyle(areaGeom, config.area.geomStyle, {}, `x*${yAxisKey}*type*extra`);
    }
  }

  geomStyle(lineGeom, config.lineGeomStyle, {
    lineWidth: lineWidth || themes['widgets-line-width'],
    lineJoin: 'round',
  }, `x*${yAxisKey}*${legendKey}*extra`);

  label({ geom: lineGeom, config: config, field: yAxisKey, extraConfigKey: 'lineLabel' });

  // 曲线默认点
  if (config.symbol) {
    let pointGeom = null;

    if (config.area && stack) {
      pointGeom = chart.point()
        .adjust('stack')
        .position(['x', yAxisKey])
        .color(legendKey, config.lineColors)
        .shape('circle')
        .size(3)
    } else {
      pointGeom = chart.point()
        .position(['x', yAxisKey])
        .color(legendKey, config.lineColors)
        .shape('circle')
        .size(3)
    }

    if (typeof config.symbol === 'object') {
      geomSize(pointGeom, config.symbol.size, 3, yAxisKey, legendKey);

      if (config.symbol.geomStyle) {
        geomStyle(pointGeom, config.symbol.geomStyle, {}, `x*${yAxisKey}*${legendKey}*extra`);
      }
    }
  }

  return lineGeom;
}