Add #3886 min characters for dropdown

RELEASE-NOTES.md

@@ -66,6 +66,7 @@
 
 **Enhancements**
 - **Site** - Added colored box shadow defaults. `ui message` now includes individual colored border shadows based on new site defaults.
+- **Dropdown** - Adds new setting `minCharacters` which sets the minimum number of characters required to start filtering results #3886
 - **Dropdown** - Added `1px` offset for current text so that the text position cursor does not overlap first pixel of text.
 - **Dropdown** - Added new convenience method `restore placeholder text`
 - **Rating** - Added new setting `fireOnInit` for rating, which defaults to `false`. When set to true `onRate` will fire when rating is initialized #3712

src/definitions/modules/dropdown.js

@@ -236,7 +236,12 @@ $.fn.dropdown = function(parameters) {
             : module.get.query()
           ;
           module.verbose('Searching for query', query);
-          module.filter(query);
+          if(module.has.minCharacters(query)) {
+            module.filter(query);
+          }
+          else {
+            module.hide();
+          }
         },
 
         select: {
@@ -2797,6 +2802,16 @@ $.fn.dropdown = function(parameters) {
           selectInput: function() {
             return ( $input.is('select') );
           },
+          minCharacters: function(searchTerm) {
+            if(settings.minCharacters) {
+              searchTerm = (searchTerm !== undefined)
+                ? String(searchTerm)
+                : String(module.get.query())
+              ;
+              return (searchTerm.length >= settings.minCharacters);
+            }
+            return true;
+          },
           firstLetter: function($item, letter) {
             var
               text,
@@ -3356,6 +3371,7 @@ $.fn.dropdown.settings = {
 
 
   apiSettings            : false,
+  minCharacters          : 1,          // Minimum characters required to trigger API call
   saveRemoteData         : true,       // Whether remote name/value pairs should be stored in sessionStorage to allow remote data to be restored on page refresh
   throttle               : 200,        // How long to wait after last user input to search remotely