Merge pull request #1247 from scireum/feature/sbi/OX-10141

Continuity: Only calls state handler restore when entry is actually changed

src/main/resources/default/assets/common/core.js.pasta

@@ -521,3 +521,44 @@ sirius.isDragleaveEventLeavingWindow = function (event) {
     }
     return false;
 }
+
+/**@
+ * Compares the two given objects for equality, allowing for nested objects.
+ *
+ * @param object1 the first object to compare
+ * @param object2 the second object to compare
+ * @returns {boolean} true if the objects are equal, false otherwise
+ */
+sirius.areObjectsDeeplyEqual = function (object1, object2) {
+    const keys1 = Object.keys(object1);
+    const keys2 = Object.keys(object2);
+
+    if (keys1.length !== keys2.length) {
+        return false;
+    }
+
+    // var is used here instead of const to keep the code compatible with IE11.
+    for (var key of keys1) {
+        const value1 = object1[key];
+        const value2 = object2[key];
+        const areObjects = sirius.isObject(value1) && sirius.isObject(value2);
+        if (areObjects && !sirius.areObjectsDeeplyEqual(value1, value2)) {
+            return false;
+        }
+        if (!areObjects && value1 !== value2) {
+            return false;
+        }
+    }
+
+    return true;
+}
+
+/**@
+ * Checks if the given value is an object.
+ *
+ * @param object the value to check
+ * @returns {boolean} true if the value is an object, false otherwise
+ */
+sirius.isObject = function (object) {
+    return object != null && typeof object === 'object';
+}

src/main/resources/default/assets/common/scripts/continuity.js.pasta

@@ -137,8 +137,9 @@ window.sirius.Continuity = (function () {
      * @param {boolean} dontSetLastState whether the internal last state should be replaced by the current history state (before the new one became active)
      */
     Continuity.prototype.handleStateChange = function (state, dontSetLastState) {
+        let stateBeforeChange = Object.assign({}, this.currentState);
         if (!dontSetLastState) {
-            this.lastState = Object.assign({}, this.currentState);
+            this.lastState = stateBeforeChange;
         }
         this.currentState = state;
 
@@ -148,7 +149,12 @@ window.sirius.Continuity = (function () {
             if (handler) {
                 const entry = state[entryKey];
                 me.log('[CONTINUITY] [INTERNAL] State handler of type "%s" called for entry: %o', entryKey, entry);
-                handler.restore.call(me, entry);
+                if (!sirius.areObjectsDeeplyEqual(stateBeforeChange[entryKey], entry)) {
+                    // We only call the handler if the specific entry has actually changed.
+                    handler.restore.call(me, entry);
+                } else {
+                    me.log('[CONTINUITY] [INTERNAL] State handler of type "%s" called for unchanged entry: %o', entryKey, entry);
+                }
             } else {
                 me.log('[CONTINUITY] [INTERNAL] State handler of type "%s" not found!', entryKey);
             }