Gracefully handle adding of no users to projects and groups

- Disable {project, group} members submit button if no users

  If no users are selected, the submit button should be disabled.

- Alert user when no users were added to {project, group}.

  When no users were selected for adding, an alert message is
  flashed that no users were added.

- Also, this commit adds a feedback when users were actually added to a
  project, in symmetry with how group members are handled.

Closes #22967, #23270.

1 files changed, 3 insertions, 2 deletions

diff --git a/app/assets/javascripts/application.js b/app/assets/javascripts/application.js
index 8a61669822c..17cbfd0e66f 100644
--- a/app/assets/javascripts/application.js
+++ b/app/assets/javascripts/application.js
@@ -83,14 +83,15 @@
   };
 
   // Disable button if text field is empty
-  window.disableButtonIfEmptyField = function(field_selector, button_selector) {
+  window.disableButtonIfEmptyField = function(field_selector, button_selector, event_name) {
+    event_name = event_name || 'input';
     var closest_submit, field;
     field = $(field_selector);
     closest_submit = field.closest('form').find(button_selector);
     if (rstrip(field.val()) === "") {
       closest_submit.disable();
     }
-    return field.on('input', function() {
+    return field.on(event_name, function() {
       if (rstrip($(this).val()) === "") {
         return closest_submit.disable();
       } else {