Adds a message when an empty string is provided (#568)

Fixes #497

Co-authored-by: Hadley Wickham <[email protected]>

NEWS.md

@@ -1,8 +1,9 @@
 # stringr (development version)
 
+* `str_view()` now displays a message when called with a zero-length character
+  vector (@LouisMPenrod, #497).
 * Adds `[[.stringr_pattern` method to go along with existing `[.stringr_pattern`
   method (@edward-burn, #569).
-
 * In `str_replace_all()`, a `replacement` function now receives all values in
   a single vector. This radically improves performance at the cost of breaking
   some existing uses (#462).

R/view.R

@@ -179,6 +179,7 @@ print.stringr_view <- function(x, ..., n = getOption("stringr.view_n", 20)) {
   }
 
   if (length(x) == 0) {
+    cli::cli_inform(c(x = "Empty `string` provided.\n"))
     return(invisible(x))
   }
 

tests/testthat/_snaps/view.md

@@ -76,10 +76,12 @@
       [3] | \n
       [4] | \t
 
-# view displays nothing for empty vectors
+# view displays message for empty vectors
 
     Code
       str_view(character())
+    Message
+      x Empty `string` provided.
 
 # can match across lines
 

tests/testthat/test-view.R

@@ -29,7 +29,7 @@ test_that("view highlights whitespace (except a space/nl)", {
   })
 })
 
-test_that("view displays nothing for empty vectors",{
+test_that("view displays message for empty vectors",{
   expect_snapshot(str_view(character()))
 })