fix: modified linkedlist maintenance func

src/utils.js

@@ -20,17 +20,12 @@ export function setUnitsHead(units) {
  * @returns units {Unit[]}
  */
 export function setNextLinks(units) {
-    const flowchartIds = units.map((u) => u.flowchartId);
+    console.log("fixing next fields");
     for (let i = 0; i < units.length - 1; i++) {
-        if (!units[i].next) {
-            // newly added units don't have next set yet => set it
-            units[i].next = units[i + 1].flowchartId;
-            if (i > 0) units[i - 1].next = units[i].flowchartId;
-        } else if (!flowchartIds.includes(units[i].next)) {
-            // newly removed units may create broken next links => fix it
-            units[i].next = units[i + 1].flowchartId;
-        }
+        units[i].next = units[i + 1].flowchartId;
     }
+    // for the last unit in the list, set next to null or undefined
+    units[units.length - 1].next = null;
     return units;
 }