Dash-canvas (R) and filter_null

[NKalavros]

Hello all,

I was trying to translate an applet from Python to R, but encountered a problem. The snippet I used was from the tutorial at: https://dashr.plotly.com/dash-canvas

And it was this:

app <- Dash$new()

app$layout(
  htmlDiv(
    list(
      htmlH5("Press down the left mouse button and draw inside the canvas"),
      dashCanvas(id = 'canvas_101')
      
      )
    )
  )


app$run_server()

Which returns:

Error in filter_null(component$props) : 
  could not find function "filter_null"

Looking at the changelog https://github.com/plotly/dashR/blob/master/CHANGELOG.md, this function has been excised

I found the function to be:

filter_null <- function(x) {
  if (length(x) == 0 || !is.list(x)) return(x)
  x[!vapply(x, is.null, logical(1))]
}

And everything works normally afterwards.