How to force networkD3::sankeyNetwork() to repeat nodes rather than circling back to same node

Question

Hi I am creating a sankey diagram to show migration. One aspect I am facing issues with is how to deal with scenarios when status doesn't change i.e. migration doesn't happen. In such scenarios, the sankey is circling back to same source, creating a circle rather than using a 'source- target' layout where both source destination is separate. I'd like to see something like

instead of following which I'm seeing now

Following is a reproducible example- I appreciate any assistance with this

library(networkD3)
library(dplyr)
links<-data.frame(
  source=c('One','Two','Two','Three','Three','Four','Four','Five','Five','Six'),
  target=c('Two','Two','Three','Three','Four','Four','Five','Five','Six','Seven'),
  value=c(78,108,27,14,31,38,17,76,10,89)
)
nodes <- data.frame(
  name=c(as.character(links$source), 
         as.character(links$target)) %>% unique()
)
links$IDsource <- match(links$source, nodes$name)-1 
links$IDtarget <- match(links$target, nodes$name)-1

sankeyNetwork(Links = links, Nodes = nodes,
              Source = "IDsource", Target = "IDtarget",
              Value = "value", NodeID = "name", 
              fontSize = 20)

Answer 1

Every node you want to see in the plot has to be uniquely identified in your nodes data.frame. If you want some unique nodes to share the same label, you can add a column to the nodes data.frame for the label and specify it to the NodeID argument... those do not need to be unique.

library(networkD3)

links <- read.csv(header = TRUE, strip.white = TRUE, text ="
source,    target,    value
One_1,     Two_2,     78
Two_2,     Two_3,     108
Two_2,     Three_3,   27
Three_3,   Three_4,   14
Three_3,   Four_4,    31
Four_4,    Four_5,    38
Four_4,    Five_5,    17
Five_5,    Five_6,    76
Five_5,    Six_6,     10
Six_6,     Seven_7,   89
")

id <- unique(c(as.character(links$source), as.character(links$target)))
label <- sub("_[0-9]", "", id)
nodes <- data.frame(id = id, label = label)

links$IDsource <- match(links$source, nodes$id)-1 
links$IDtarget <- match(links$target, nodes$id)-1

sankeyNetwork(Links = links, Nodes = nodes,
              Source = "IDsource", Target = "IDtarget",
              Value = "value", NodeID = "label", 
              fontSize = 20)