Link to default theme and treat new being null as new being missing.

Author: VisruthSK

R/theme-current.R

@@ -91,12 +91,10 @@ get_theme <- function() {
 theme_get <- get_theme
 
 #' @rdname get_theme
-#' @param new new theme (a list of theme elements). Sets theme to the default (theme_grey) if `new` isn't supplied.
+#' @param new new theme (a list of theme elements). Sets theme to the default ([theme_grey()]) if `new` isn't supplied.
 #' @export
 set_theme <- function(new) {
-  if (missing(new)) {
-    new <- ggplot_global$theme_default
-  }
+  new <- new %||% ggplot_global$theme_default
   check_object(new, is_theme, "a {.cls theme} object")
   old <- ggplot_global$theme_current
   ggplot_global$theme_current <- new