move exported fun to helpers.R file (#7331)

Author: jangorecki

R/helpers.R

@@ -0,0 +1,12 @@
+# here we have helpers functions that DT exports, on contrary to utils.R file
+
+# convert char to factor retaining order #4837
+fctr = function(x, levels=unique(x), ..., sort=FALSE, rev=FALSE) {
+  if (!isTRUEorFALSE(sort))
+    stopf("argument 'sort' must be TRUE or FALSE")
+  if (!isTRUEorFALSE(rev))
+    stopf("argument 'rev' must be TRUE or FALSE")
+  if (sort) levels = sort(levels)
+  if (rev) levels = frev(levels)
+  factor(x, levels=levels, ...)
+}

R/utils.R

@@ -220,17 +220,6 @@ rss = function() {  #5515 #5517
   # nocov end
 }
 
-# convert char to factor retaining order #4837
-fctr = function(x, levels=unique(x), ..., sort=FALSE, rev=FALSE) {
-  if (!isTRUEorFALSE(sort))
-    stopf("argument 'sort' must be TRUE or FALSE")
-  if (!isTRUEorFALSE(rev))
-    stopf("argument 'rev' must be TRUE or FALSE")
-  if (sort) levels = sort(levels)
-  if (rev) levels = frev(levels)
-  factor(x, levels=levels, ...)
-}
-
 formula_vars = function(f, x) { # .formula2varlist is not API and seems to have appeared after R-4.2, #6841
   terms <- terms(f)
   setNames(