Scala.js联合类型

Question

我正在为Scala.js (v0.6.13)使用HighCharts facade，在我的图表上配置十字光标时遇到了困难。我的理解是，当我看到Scala.js联合类型声明时：

val crosshair: UndefOr[|[Boolean, CleanJsObject[YAxisCrosshair]]]

十字准线可以是布尔值也可以是YAxisCrosshair？

如果是这样，我的十字准线设置为true的声明可以正确编译：

override val yAxis: Cfg[YAxis] = YAxis(
  gridLineWidth = 0,
  minorGridLineWidth = 0,
  opposite = false,
  labels = YAxisLabels(
    align = "right",
    format = "{value:.8f}"
  ),
  crosshair = true
) 

但是，当我将十字准线设置为YAxisCrosshair时，我的项目无法编译。

override val yAxis: Cfg[YAxis] = YAxis(
  gridLineWidth = 0,
  minorGridLineWidth = 0,
  opposite = false,
  labels = YAxisLabels(
    align = "right",
    format = "{value:.8f}"
  ),
  crosshair = YAxisCrosshair(
    snap = false,
    label = YAxisCrosshairLabel(
      format = "{value:.8f}"
    )
  )
)

后者的结果是：

type mismatch;
  found   : com.highstock.config.YAxisCrosshair
  required: scala.scalajs.js.UndefOr[scala.scalajs.js.|        [Boolean,com.highcharts.CleanJsObject[com.highstock.config.YAxisCrosshair]]]

这里我漏掉了什么？

Answer 1

我想我已经找到答案了。这是需要做的事情：

override val yAxis: Cfg[YAxis] = YAxis(
  gridLineWidth = 0,
  minorGridLineWidth = 0,
  opposite = false,
  labels = YAxisLabels(
    align = "right",
    format = "{value:.8f}"
  ),
  crosshair = YAxisCrosshair(
    snap = false,
    label = YAxisCrosshairLabel(
      format = "{value:.8f}"
    )
  ): CleanJsObject[YAxisCrosshair]
)