I've tried
nodes <- data.frame(id = 1:3, group = c("B", "A", "B"))
edges <- data.frame(from = c(1,2), to = c(2,3))
visNetwork(nodes, edges) %>% visExport(type = "pdf")
and unfortunately, the pdf generated doesn't contain a vectorial image of my network but a bad quality raster image.
How can I get a high-quality vector pdf file?