map（）方法的妙用、data &&data.map（）

  const lineY = useMemo(() => {
    var color = ['rgba(23, 255, 243', 'rgba(119,61,190'];
    //如果data有值则执行&&后面的   如果data为空则不执行
    return (
      data.value &&
      data.value.map((item, index) => {
        return {
          name: item.name,
          type: 'line',
          color: color[index] + ')',
          smooth: true,
          areaStyle: {
            normal: {
              color: new echarts.graphic.LinearGradient(
                0,
                0,
                0,
                1,
                [
                  {
                    offset: 0,
                    color: color[index] + ', 0.3)',
                  },
                  {
                    offset: 0.8,
                    color: color[index] + ', 0)',
                  },
                ],
                false,
              ),
              shadowColor: 'rgba(0, 0, 0, 0.1)',
              shadowBlur: 10,
            },
          },
          symbol: 'circle',
          symbolSize: 5,
          data: item.data,
        };
      })
    );
  }, [data]);