Epic tree move child with drag and drop

- Review feedback

ee/app/assets/javascripts/related_items_tree/components/tree_root.vue

@@ -51,7 +51,7 @@ export default {
     },
     onMove(e) {
       const item = e.relatedContext.element;
-      if (item && item.type && item.type === ChildType.Epic)
+      if (item?.type === ChildType.Epic)
         this.toggleItem({
           parentItem: item,
           isDragging: true,

ee/app/assets/javascripts/related_items_tree/store/actions.js

@@ -470,9 +470,9 @@ export const moveItem = (
   let isFirstChild = false;
   const newParentChildren = state.children[newParentItem.parentReference];
 
-  if (newParentChildren !== undefined && newParentChildren.length > 0) {
+  if (newParentChildren?.length > 0) {
     adjacentItem = newParentChildren[newIndex];
-    if (adjacentItem === undefined) {
+    if (!adjacentItem) {
       adjacentItem = newParentChildren[newParentChildren.length - 1];
       relativePosition = relativePositions.Before;
     }

ee/spec/frontend/related_items_tree/store/actions_spec.js

@@ -1379,15 +1379,17 @@ describe('RelatedItemTree', () => {
             }),
           );
 
+          const payload = {
+            oldParentItem: mockParentItem,
+            newParentItem: mockParentItem2,
+            targetItem: mockItems[1],
+            newIndex: 1,
+            oldIndex: 0,
+          };
+
           testAction(
             actions.moveItem,
-            {
-              oldParentItem: mockParentItem,
-              newParentItem: mockParentItem2,
-              targetItem: mockItems[1],
-              newIndex: 1,
-              oldIndex: 0,
-            },
+            payload,
             state,
             [
               {
@@ -1405,13 +1407,7 @@ describe('RelatedItemTree', () => {
             [
               {
                 type: 'receiveMoveItemFailure',
-                payload: {
-                  oldParentItem: mockParentItem,
-                  newParentItem: mockParentItem2,
-                  targetItem: mockItems[1],
-                  newIndex: 1,
-                  oldIndex: 0,
-                },
+                payload,
               },
             ],
           );
@@ -1420,15 +1416,17 @@ describe('RelatedItemTree', () => {
         it('should perform MOVE_ITEM mutation before request and dispatch `receiveReorderItemFailure` on request failure', () => {
           jest.spyOn(epicUtils.gqClient, 'mutate').mockReturnValue(Promise.reject());
 
+          const payload = {
+            oldParentItem: mockParentItem,
+            newParentItem: mockParentItem2,
+            targetItem: mockItems[1],
+            newIndex: 1,
+            oldIndex: 0,
+          };
+
           testAction(
             actions.moveItem,
-            {
-              oldParentItem: mockParentItem,
-              newParentItem: mockParentItem2,
-              targetItem: mockItems[1],
-              newIndex: 1,
-              oldIndex: 0,
-            },
+            payload,
             state,
             [
               {
@@ -1446,13 +1444,7 @@ describe('RelatedItemTree', () => {
             [
               {
                 type: 'receiveMoveItemFailure',
-                payload: {
-                  oldParentItem: mockParentItem,
-                  newParentItem: mockParentItem2,
-                  targetItem: mockItems[1],
-                  newIndex: 1,
-                  oldIndex: 0,
-                },
+                payload,
               },
             ],
           );

ee/spec/frontend/related_items_tree/store/mutations_spec.js

@@ -565,6 +565,16 @@ describe('RelatedItemsTree', () => {
       });
 
       describe(types.MOVE_ITEM, () => {
+        const defaultPayload = {
+          oldParentItem: {
+            reference: '&1',
+          },
+          targetItem: 'bar',
+          oldIndex: 1,
+          newIndex: 0,
+          isFirstChild: false,
+        };
+
         it('should move an item from one parent to another with children based on provided indexes', () => {
           const newParentItem = {
             parentReference: '&2',
@@ -574,14 +584,8 @@ describe('RelatedItemsTree', () => {
           state.children[newParentItem.parentReference] = ['baz'];
 
           mutations[types.MOVE_ITEM](state, {
-            oldParentItem: {
-              reference: '&1',
-            },
+            ...defaultPayload,
             newParentItem,
-            targetItem: 'bar',
-            oldIndex: 1,
-            newIndex: 0,
-            isFirstChild: false,
           });
 
           expect(state.children[state.parentItem.reference]).toEqual(
@@ -600,13 +604,8 @@ describe('RelatedItemsTree', () => {
           state.children[state.parentItem.reference] = ['foo', 'bar'];
 
           mutations[types.MOVE_ITEM](state, {
-            oldParentItem: {
-              reference: '&1',
-            },
+            ...defaultPayload,
             newParentItem,
-            targetItem: 'bar',
-            oldIndex: 1,
-            newIndex: 0,
             isFirstChild: true,
           });
 
@@ -627,13 +626,9 @@ describe('RelatedItemsTree', () => {
           state.childrenFlags[state.parentItem.reference] = { itemHasChildren: true };
 
           mutations[types.MOVE_ITEM](state, {
-            oldParentItem: {
-              reference: '&1',
-            },
+            ...defaultPayload,
             newParentItem,
-            targetItem: 'bar',
             oldIndex: 0,
-            newIndex: 0,
             isFirstChild: true,
           });