add helper number_unnamed function (see #18)

NAMESPACE

@@ -3,6 +3,7 @@
 export(jsonedit)
 export(jsoneditOutput)
 export(jsonedit_gadget)
+export(number_unnamed)
 export(reactjson)
 export(reactjsonOutput)
 export(renderJsonedit)

NEWS.md

@@ -1,7 +1,8 @@
 # listviewer 1.4.0
 
 * add `elementId` to the `jsonedit` function
-* update `react-json` to [`0.2.1`]
+* update `react-json` to [`0.2.1`](https://github.com/arqex/react-json/releases/tag/0.2.1)
+* add helper `number_unnamed` function (see [issue](https://github.com/timelyportfolio/listviewer/issues/18))
 
 # listviewer 1.3
 

R/utils.R

@@ -1,5 +1,4 @@
 #' @keywords internal
-
 named_vec2list <- function(listx){
   # to avoid toJSON keep_vec_names warnings
   #  with named vectors
@@ -22,3 +21,59 @@ list_proper_form <- function(listdata){
   }
 }
 
+#' Recurse Over Nested Lists
+#'
+#' Like \code{rapply} but recurses over nested lists and
+#' retain \code{attributes} and \code{names}.
+#'
+#' @param l \code{list} over which we would like to recurse
+#' @param func \code{function} to apply to the list
+#' @param ... arguments for the \code{func}
+#'
+#' @keywords internal
+recurse <- function(l, func, ...) {
+l <- func(l, ...)
+if(is.list(l) && length(l)>0){
+  lapply(
+    l,
+    function(ll){
+      recurse(ll, func, ...)
+    }
+  )
+} else {
+  l
+}
+}
+
+#' @keywords internal
+add_number_names <- function(l){
+  if(length(l)>0 && is.null(names(l))){
+    names(l) <- seq_len(length(l))
+  }
+  l
+}
+
+
+#' Number Starting at \code{1}
+#'
+#' JavaScript starts at \code{0}, but R starts at \code{1}.
+#' This means unnamed lists and vectors are indexed starting at
+#' \code{0} in listviewer widgets.  This little helper function
+#' tries to resolve the disconnect by assigning sequential numbers
+#' starting at \code{1} to names for unnamed \code{lists} and \code{vectors}.
+#' Please note though that using \code{number_unnamed} will potentially
+#' cause difficulties serializing back and forth between JavaScript and R.
+#'
+#' @param l \code{list}
+#'
+#' @examples
+#' library(listviewer)
+#' jsonedit(
+#'   number_unnamed(list(x=list(letters[1:3])))
+#' )
+#'
+#' @export
+
+number_unnamed <- function(l) {
+  recurse(l, add_number_names)
+}