Issue #1149078 by vasike, wuinfo - Bill Wu, dww, Gauravvvv, Marios...

Issue #1149078 by vasike, wuinfo - Bill Wu, dww, Gauravvvv, Marios Anagnostopoulos, peterpoe, VladimirAus, legolasbo, mgifford, dalin, jrb, himanshupathak3, utsavsharma, alwaysworking, Daniel Kulbe, arcaneadam, arnaud-brugnon, danflanagan8, uzlov, DamienMcKenna, Kuntyi, COBadger, Neslee Canil Pinto, esod, nod, CKIDOW: States API doesn't work with multiple select fields

Closes #1149078

core/misc/states.js

@@ -149,6 +149,7 @@
    *
    * @prop {function} RegExp
    * @prop {function} Function
+   * @prop {function} Array
    * @prop {function} Number
    */
   states.Dependent.comparisons = {
@@ -159,6 +160,15 @@
       // The "reference" variable is a comparison function.
       return reference(value);
     },
+    Array(reference, value) {
+      // Make sure value is an array.
+      if (!Array.isArray(value)) {
+        return false;
+      }
+
+      // The arrays values should match.
+      return JSON.stringify(reference.sort()) === JSON.stringify(value.sort());
+    },
     Number(reference, value) {
       // If "reference" is a number and "value" is a string, then cast
       // reference as a string before applying the strict comparison in