Handle missing neighbor data when switching to another element

vue/Element/Main.vue

@@ -220,7 +220,7 @@ export default {
       })
     },
     isNeighbor (id) {
-      const neighbors = this.neighbors[this.id] && this.neighbors[this.id].results.map(n => n.element.id)
+      const neighbors = this.neighbors[this.id]?.results.map(n => n.element.id)
       return neighbors && neighbors.includes(this.id) && neighbors.includes(id)
     }
   },

vue/HeaderActions.vue

@@ -473,17 +473,17 @@ export default {
       return this.getType(this.element.type)
     },
     totalChildrenCount () {
-      return this.elementId && this.childrenPagination[this.elementId] && this.childrenPagination[this.elementId].count
+      return this.elementId && this.childrenPagination[this.elementId]?.count
     },
     firstParentId () {
       // Returns the first parent element of this element. Used to redirect to a parent when deleting the element
-      if (!this.elementId || !this.neighbors[this.elementId] || !this.neighbors[this.elementId].results) return null
+      if (!this.elementId || !this.neighbors[this.elementId]?.results) return null
       const neighbor = this.neighbors[this.elementId].results.find(n => n.element && n.element.id === this.elementId)
       // Prevent errors on null parents since ListElementNeighbors can return null parents for paths with 'ghost elements'
       return [...neighbor?.parents].reverse().find(parent => parent !== null)?.id
     },
     elementDirectParents () {
-      if (!this.elementId || !this.neighbors[this.elementId] || !this.neighbors[this.elementId].results) return null
+      if (!this.elementId || !this.neighbors[this.elementId]?.results) return null
       // Fetch all direct parents of this element.
       const firstParents = this.neighbors[this.elementId].results.filter(n => n.element && n.element.id === this.elementId).map(n => n.parents[n.parents.length - 1])
       // Prevent returning duplicated parents by filtering out identical objects.