Fix map_arg and other utilities

- compact() returns NULL if all elements are NULL
- map_arg handles no .args provided
- is_htmlish() actually works now

R/utils.R

@@ -12,11 +12,17 @@ dots2list <- function(...) {
 }
 
 map_arg <- function(..., .f, .args = NULL) {
-  mapply(.f, ..., MoreArgs = compact(.args), SIMPLIFY = FALSE, USE.NAMES = TRUE)
+  .args <- compact(.args)
+  if (is.null(.args)) {
+    mapply(.f, ..., SIMPLIFY = FALSE, USE.NAMES = TRUE)
+  } else {
+    mapply(.f, ..., MoreArgs = compact(.args), SIMPLIFY = FALSE, USE.NAMES = TRUE)
+  }
 }
 
 compact <- function(x) {
-  x[!vapply(x, is.null, logical(1))]
+  x <- x[!vapply(x, is.null, logical(1))]
+  if (length(x)) x else NULL
 }
 
 tag_function <- function(.tag = "div") {
@@ -57,9 +63,9 @@ validate_value <- function(value = NULL, choices, several.ok = TRUE, value_name
   } else if (!is.null(value) && !length(value)) NULL
 }
 
-is_html <- function(x) inherits(class(x), "html")
-is_tagList <- function(x) inherits(class(x), "shiny.tag.list")
-is_tag <- function(x) inherits(class(x), "shiny.tag")
+is_html <- function(x) inherits(x, "html")
+is_tagList <- function(x) inherits(x, "shiny.tag.list")
+is_tag <- function(x) inherits(x, "shiny.tag")
 is_htmlish <- function(x) is_html(x) | is_tag(x) | is_tagList(x)
 
 c_is <- function(x) {

tests/testthat/test-utils.R

@@ -0,0 +1,22 @@
+context("test-utils")
+
+test_that("map_arg", {
+  expect_equal(map_arg("a", "b", "c", .f = paste), list(a = "a b c"))
+  expect_equal(map_arg("a", "b", "c", .f = paste, .args = list(sep = ",")),
+               list(a = "a,b,c"))
+  expect_equal(map_arg("a", "b", "c", .f = paste, .args = list(sep = ",", collapse = NULL)),
+               list(a = "a,b,c"))
+})
+
+test_that("compact", {
+  expect_equal(compact(list(x = NULL, y = 1)), list(y = 1))
+  expect_equal(compact(list(x = list(NULL), y = 1)), list(x = list(NULL), y = 1))
+  expect_null(compact(list(x = NULL, y = NULL)))
+})
+
+test_that("is_htmlish", {
+  expect_true(is_html(htmltools::HTML("test")))
+  expect_true(is_tagList(htmltools::tagList("test")))
+  expect_true(is_tag(htmltools::tag("div", list("test"))))
+  expect_true(is_htmlish(tag_p("test")))
+})