Resolved VUFIND-603 (added optional alphabetical sorting of browse lists).

config/vufind/config.ini

@@ -642,6 +642,10 @@ region          = true      ; allow browsing of region subdivisions
 era             = true      ; allow browsing of era subdivisions
 ; You can use this setting to change the default alphabet provided for browsing:
 ;alphabet_letters = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+; Uncomment to sort lists alphabetically (instead of by popularity); note that
+; this will not changed the values returned -- you will still get only the
+; <result_limit> most popular entries -- it only affects display order.
+;alphabetical_order = true
 
 ; This section controls which record export methods are displayed on the Record
 ; view screen.  Note that some options may be disabled for records that do not

module/VuFind/src/VuFind/Controller/BrowseController.php

@@ -581,6 +581,17 @@ class BrowseController extends AbstractBase
         $params->setFacetSort($sort);
         $result = $searchObject->getFacetList();
         if (isset($result[$facet])) {
+            // Sort facets alphabetically if configured to do so:
+            if (isset($this->config->Browse->alphabetical_order)
+                && $this->config->Browse->alphabetical_order) {
+                if (isset($this->config->Site->locale)) {
+                    setlocale(LC_ALL, $this->config->Site->locale . ".utf8");
+                    $callback = function ($a, $b) {
+                        return strcoll($a['displayText'], $b['displayText']);
+                    };
+                    usort($result[$facet]['list'], $callback);
+                }
+            }
             return $result[$facet]['list'];
         } else {
             return array();