From 24ed83749f683508d94d9dfa3c80a93f06ed5697 Mon Sep 17 00:00:00 2001
From: Tymoteusz Makowski <tymoteusz.makowski@appsilon.com>
Date: Tue, 19 Mar 2024 23:35:42 +0100
Subject: [PATCH] fix!: clear single-selection dropdown on `character(0)` and
 `""`

Prior to this change only multi-selection dropdown could be cleared.
This change makes `update_dropdown_input` behavior analogous to
`shiny::updateSelectInput`.

Note: this is a breaking change. Prior to this commit updating with
`character(0)` or `""` did not have any effect.
---
 R/dropdown.R                        | 3 ++-
 inst/www/shiny-semantic-dropdown.js | 4 ++++
 man/update_dropdown_input.Rd        | 3 ++-
 3 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/R/dropdown.R b/R/dropdown.R
index d04e23ea..4bb88156 100644
--- a/R/dropdown.R
+++ b/R/dropdown.R
@@ -149,7 +149,8 @@ selectInput <- function(inputId, label, choices, selected = NULL, multiple = FAL
 #' @param input_id The id of the input object
 #' @param choices All available options one can select from. If no need to update then leave as \code{NULL}
 #' @param choices_value What reactive value should be used for corresponding choice.
-#' @param value The initially selected value.
+#' @param value A value to update dropdown to. \code{character(0)} and \code{""} clear the dropdown.
+#' \code{NULL} (the default) does not change selection.
 #'
 #' @examples
 #' if (interactive()) {
diff --git a/inst/www/shiny-semantic-dropdown.js b/inst/www/shiny-semantic-dropdown.js
index b32988aa..6ea29780 100644
--- a/inst/www/shiny-semantic-dropdown.js
+++ b/inst/www/shiny-semantic-dropdown.js
@@ -32,6 +32,10 @@ $.extend(semanticDropdownBinding, {
 
   // Given the DOM element for the input, set the value.
   setValue: function(el, value) {
+    if (value === '') {
+      $(el).dropdown('clear');
+      return;
+    }
     if ($(el).hasClass('multiple')) {
       $(el).dropdown('clear', true);
       value.split(",").map(v => $(el).dropdown('set selected', v));
diff --git a/man/update_dropdown_input.Rd b/man/update_dropdown_input.Rd
index 17ed4c83..4bf5fee4 100644
--- a/man/update_dropdown_input.Rd
+++ b/man/update_dropdown_input.Rd
@@ -21,7 +21,8 @@ update_dropdown_input(
 
 \item{choices_value}{What reactive value should be used for corresponding choice.}
 
-\item{value}{The initially selected value.}
+\item{value}{A value to update dropdown to. \code{character(0)} and \code{""} clear the dropdown.
+\code{NULL} (the default) does not change selection.}
 }
 \description{
 Change the value of a \code{\link{dropdown_input}} input on the client.