Function to get descendant node numbers

So, I'm working on a different project that required me to write a function to pull out the descendant node (& tip) numbers from any internal node on the tree. Even though I feel like I've done this before, I struggled coming up with something that made sense. This is what I ended up with:

getDescendants<-function(tree,node,curr=NULL){
  if(is.null(curr)) curr<-vector()
  daughters<-tree$edge[which(tree$edge[,1]==node),2]
  curr<-c(curr,daughters)
  w<-which(daughters>=length(tree$tip))
  if(length(w)>0) for(i in 1:length(w))
    curr<-getDescendants(tree,daughters[w[i]],curr)
  return(curr)
}

Here's a quick example of how it works:

> tree<-pbtree(n=10)
> tree$tip.label<-1:10
> # this lines up tip numbers & labels for simplicity
> par(mar=c(1,1,1,1)) # set margins
> plot(tree,font=1); nodelabels(bg="white")


Now we can pull the numbers for the descendant nodes & tips for any internal node. For instance:

> getDescendants(tree,node=17)
[1] 18 6 7 8
> getDescendants(tree,node=12)
[1] 16 15 4 5 2 3
> getDescendants(tree,node=19)
[1] 9 10

Anyway, seems to work, but if anyone is aware of an existing function for this, please pass it along.