How to get yDomain value in ReactVis

Question

In React-vis, I display the cursor position of the mouse using a LineSeries. I would like it to extend along all the vertical extent of the FlexibleXYPlot in which it's included:

Image of the cursor on a ReactVis plot

¿How can I get the value of the yDomain of the plot?

Thank you!

Edit

I am using React-vis in clojurescript. I got the line seen in the first image with this code:

[:> rvis/LineSeries {:data [{:x @nearest-x :y y-min}{:x @nearest-x :y y-max}]
                     :strokeStyle "dashed" :color "black"
                     :opacity (if @button-pressed? .5 0)}]

And I needed to compute the value of y-min and y-max (that was the meaning of my question).

But then I realized that I can use the Crosshair facility:

[:> rvis/Crosshair {:values [{:x @nearest-x :y 0}] 
                    :style {:line {:opacity (if @button-pressed? .5 0)}}}
                   [:div]]

Crosshair in React-vis

It's difficult to see (it's under the cursor), because I still can't manage to change its color. I thought that this would work:

[:> rvis/Crosshair {:values [{:x @nearest-x :y 0}] 
                    :style {:line {:color "#000"
                                   :opacity (if @button-pressed? .5 0)}}}
                   [:div]]

But it doesn't. I think this would be another question. :)

Edit 2

It was :background "black" instead of :color "black". I got it reading the file plot.scss. :)