require ggplot2 >= 2.1

Author: cpsievert

DESCRIPTION

@@ -20,7 +20,7 @@ Description: Easily translate ggplot2 graphs to an interactive web-based version
 URL: https://plot.ly/r, https://github.com/ropensci/plotly
 BugReports: https://github.com/ropensci/plotly/issues
 Depends:
-    ggplot2 (>= 2.0.0)
+    ggplot2 (>= 2.1.0)
 Imports:
     scales,
     httr,

R/layers2traces.R

@@ -85,7 +85,9 @@ layers2traces <- function(data, prestats_data, layers, layout, scales, labels) {
       # name in the legend entries
       lab <- labels[legendVars]
       vals <- key[paste0(legendVars, "_domain")]
-      valz <- Map(function(x, y) { paste0(x, ": ", y) }, lab, vals)
+      valz <- Map(function(x, y) { 
+        if (nchar(x) > 0) paste0(x, ": ", y) else y
+      }, lab, vals)
       entries <- Reduce(function(x, y) {
         if (identical(x, y)) x else paste0(x, "<br>", y)
       }, valz)