So I am trying to implement a tool tip for my line chart using Mark's answer/example from here Multiseries line chart with mouseover tooltip
I'm able to get the tooltip line appear as I hover over my data points however I'm blocked by an error in I assume my x.invert function.
Uncaught ReferenceError: x is not defined
I've checked to see if this is supported d3v4 and researched other examples but no luck.
in my Here is my full code in jsfiddle, thanks in advance.