Using a simple data frame to illustrate this problem:
df <- data.frame(x=c(1,2,3), y1=c(1,2,3), y2=c(3,4,5))
The single time series chart is simple:
hPlot(y="y1", x="x", data=df)
It is impossible to figure out how to group both y1 and y2 together. Tried this, but it returns an error
> hPlot(x='x', y=c('y1','y2'), data=df)
Error in .subset2(x, i, exact = exact) : subscript out of bounds
Checking the code in hPlot, where it uses [[to extract a single column from input data.frame, does this mean that it works only for individual time series?
hPlot <- highchartPlot <- function(..., radius = 3, title = NULL, subtitle = NULL, group.na = NULL){
rChart <- Highcharts$new()
d <- getLayer(...)
data <- data.frame(
x = d$data[[d$x]],
y = d$data[[d$y]]
)