feat(canvas): enhance edge insertion animations and update reflow duration

- Added a new CSS animation for edge insertion to improve visual feedback during node creation.
- Updated the edge insertion reflow duration from 997ms to 1297ms for smoother transitions.
- Refactored related components to support the new animation and ensure consistent behavior across the canvas.
- Enhanced tests to validate the new edge insertion features and animations.

app/globals.css

@@ -145,6 +145,17 @@
   }
 }
 
+@keyframes ls-edge-insert-enter {
+  0% {
+    opacity: 0;
+    scale: 0.82;
+  }
+  100% {
+    opacity: 1;
+    scale: 1;
+  }
+}
+
 .ls-connection-line-marching {
   animation: ls-connection-dash-offset 0.4s linear infinite;
 }
@@ -250,11 +261,18 @@
 
   .react-flow.canvas-edge-insert-reflowing .react-flow__node {
     transition-property: transform;
-    transition-duration: var(--ls-edge-insert-reflow-duration, 997ms);
+    transition-duration: var(--ls-edge-insert-reflow-duration, 1297ms);
     transition-timing-function: cubic-bezier(0.68, -0.6, 0.32, 1.6);
     will-change: transform;
   }
 
+  .react-flow__node.canvas-edge-insert-enter,
+  .react-flow__node .canvas-edge-insert-enter {
+    animation: ls-edge-insert-enter 300ms cubic-bezier(0.68, -0.6, 0.32, 1.6) both;
+    transform-origin: center center;
+    will-change: scale, opacity;
+  }
+
   @media (prefers-reduced-motion: reduce) {
     .react-flow.canvas-scissors-mode .react-flow__edge:not(.temp) .react-flow__edge-path {
       transition: none;
@@ -263,5 +281,13 @@
     .react-flow.canvas-edge-insert-reflowing .react-flow__node {
       transition: none;
     }
+
+    .react-flow__node.canvas-edge-insert-enter,
+    .react-flow__node .canvas-edge-insert-enter {
+      animation: none;
+      opacity: 1;
+      scale: 1;
+      will-change: auto;
+    }
   }
 }

components/canvas/__tests__/use-canvas-sync-engine-hook.test.tsx

@@ -90,9 +90,17 @@ const latestHookValueRef: {
 
 (globalThis as typeof globalThis & { IS_REACT_ACT_ENVIRONMENT?: boolean }).IS_REACT_ACT_ENVIRONMENT = true;
 
-function HookHarness({ canvasId }: { canvasId: Id<"canvases"> }) {
+function HookHarness({
-  const [, setNodes] = useState<RFNode[]>([]);
+  canvasId,
-  const [edges, setEdges] = useState<RFEdge[]>([]);
+  initialNodes = [],
+  initialEdges = [],
+}: {
+  canvasId: Id<"canvases">;
+  initialNodes?: RFNode[];
+  initialEdges?: RFEdge[];
+}) {
+  const [nodes, setNodes] = useState<RFNode[]>(initialNodes);
+  const [edges, setEdges] = useState<RFEdge[]>(initialEdges);
   const edgesRef = useRef<RFEdge[]>(edges);
   const deletingNodeIds = useRef(new Set<string>());
   const [, setAssetBrowserTargetNodeId] = useState<string | null>(null);
@@ -120,10 +128,15 @@ function HookHarness({ canvasId }: { canvasId: Id<"canvases"> }) {
     latestEdgesRef.current = edges;
   }, [edges]);
 
+  useEffect(() => {
+    latestNodesRef.current = nodes;
+  }, [nodes]);
+
   return null;
 }
 
 const latestEdgesRef: { current: RFEdge[] } = { current: [] };
+const latestNodesRef: { current: RFNode[] } = { current: [] };
 
 function setNavigatorOnline(online: boolean) {
   Object.defineProperty(window.navigator, "onLine", {
@@ -139,6 +152,7 @@ describe("useCanvasSyncEngine hook wiring", () => {
   afterEach(async () => {
     latestHookValueRef.current = null;
     latestEdgesRef.current = [];
+    latestNodesRef.current = [];
     setNavigatorOnline(true);
     mocks.mutationMocks.clear();
     vi.clearAllMocks();
@@ -281,4 +295,97 @@ describe("useCanvasSyncEngine hook wiring", () => {
       latestEdgesRef.current.some((edge) => edge.id === "optimistic_edge_req-2"),
     ).toBe(false);
   });
+
+  it("adds optimistic split node and edges immediately in online mode before mutation resolves", async () => {
+    let createSplitResolver!: (value: string) => void;
+    const createSplitPromise = new Promise<string>((resolve) => {
+      createSplitResolver = resolve;
+    });
+    const createSplitMutation = vi.fn(() => createSplitPromise);
+    Object.assign(createSplitMutation, {
+      withOptimisticUpdate: () => createSplitMutation,
+    });
+    mocks.mutationMocks.set("nodes.createWithEdgeSplit", createSplitMutation);
+
+    container = document.createElement("div");
+    document.body.appendChild(container);
+    root = createRoot(container);
+
+    await act(async () => {
+      root?.render(
+        <HookHarness
+          canvasId={asCanvasId("canvas-1")}
+          initialNodes={[
+            {
+              id: "node-source",
+              type: "note",
+              position: { x: 0, y: 0 },
+              data: {},
+              style: { width: 120, height: 80 },
+            },
+            {
+              id: "node-target",
+              type: "note",
+              position: { x: 360, y: 0 },
+              data: {},
+              style: { width: 120, height: 80 },
+            },
+          ]}
+          initialEdges={[
+            {
+              id: "edge-base",
+              source: "node-source",
+              target: "node-target",
+              sourceHandle: "source-handle",
+              targetHandle: "target-handle",
+            },
+          ]}
+        />,
+      );
+    });
+
+    let pendingCreateSplit: Promise<Id<"nodes">> | undefined;
+    await act(async () => {
+      pendingCreateSplit = latestHookValueRef.current?.actions.createNodeWithEdgeSplit({
+        canvasId: asCanvasId("canvas-1"),
+        type: "note",
+        positionX: 180,
+        positionY: 0,
+        width: 140,
+        height: 100,
+        data: {},
+        splitEdgeId: "edge-base" as Id<"edges">,
+        splitSourceHandle: "source-handle",
+        splitTargetHandle: "target-handle",
+        newNodeSourceHandle: "new-source-handle",
+        newNodeTargetHandle: "new-target-handle",
+        clientRequestId: "split-1",
+      });
+      await Promise.resolve();
+    });
+
+    expect(
+      latestNodesRef.current.find((node) => node.id === "optimistic_split-1"),
+    ).toMatchObject({
+      className: "canvas-edge-insert-enter",
+    });
+    expect(
+      latestEdgesRef.current.some((edge) => edge.id === "edge-base"),
+    ).toBe(false);
+    expect(
+      latestEdgesRef.current.some(
+        (edge) => edge.id === "optimistic_edge_split-1_split_a",
+      ),
+    ).toBe(true);
+    expect(
+      latestEdgesRef.current.some(
+        (edge) => edge.id === "optimistic_edge_split-1_split_b",
+      ),
+    ).toBe(true);
+
+    createSplitResolver("node-real-split-1");
+    await act(async () => {
+      await pendingCreateSplit;
+    });
+  });
 });

components/canvas/canvas.tsx

@@ -82,7 +82,7 @@ interface CanvasInnerProps {
   canvasId: Id<"canvases">;
 }
 
-const EDGE_INSERT_REFLOW_SETTLE_MS = 997;
+const EDGE_INSERT_REFLOW_SETTLE_MS = 1297;
 
 function CanvasInner({ canvasId }: CanvasInnerProps) {
   const t = useTranslations('toasts');

components/canvas/use-canvas-edge-insertions.ts

@@ -27,7 +27,7 @@ export type EdgeInsertMenuState = {
 };
 
 const EDGE_INSERT_GAP_PX = 10;
-const DEFAULT_REFLOW_SETTLE_MS = 997;
+const DEFAULT_REFLOW_SETTLE_MS = 1297;
 
 function waitForReflowSettle(ms: number): Promise<void> {
   return new Promise((resolve) => {

components/canvas/use-canvas-sync-engine.ts

@@ -746,8 +746,6 @@ export function useCanvasSyncEngine({
     ]);
   });
 
-  const createNodeWithEdgeSplitMut = useMutation(api.nodes.createWithEdgeSplit);
-
   const createEdge = useMutation(api.edges.create).withOptimisticUpdate(
     (localStore, args) => {
       const edgeList = localStore.getQuery(api.edges.list, {
@@ -849,7 +847,10 @@ export function useCanvasSyncEngine({
 
   const addOptimisticNodeLocally = useCallback(
     (
-      args: Parameters<typeof createNode>[0] & { clientRequestId: string },
+      args: Parameters<typeof createNode>[0] & {
+        clientRequestId: string;
+        className?: string;
+      },
     ): Id<"nodes"> => {
       const optimisticNodeId = `${OPTIMISTIC_NODE_PREFIX}${args.clientRequestId}`;
       setNodes((current) => {
@@ -866,6 +867,7 @@ export function useCanvasSyncEngine({
             style: { width: args.width, height: args.height },
             parentId: args.parentId as string | undefined,
             zIndex: args.zIndex,
+            className: args.className,
             selected: false,
           },
         ];
@@ -1390,15 +1392,24 @@ export function useCanvasSyncEngine({
   );
 
   const runCreateNodeWithEdgeSplitOnlineOnly = useCallback(
-    async (args: Parameters<typeof createNodeWithEdgeSplitMut>[0]) => {
+    async (args: Parameters<typeof createNodeWithEdgeSplitRaw>[0]) => {
       const clientRequestId = args.clientRequestId ?? crypto.randomUUID();
       const payload = { ...args, clientRequestId };
+      const splitEdgeId = payload.splitEdgeId as string;
 
-      if (isSyncOnline) {
+      controller.pendingConnectionCreatesRef.current.add(clientRequestId);
-        return await createNodeWithEdgeSplitMut(payload);
-      }
 
-      const optimisticNodeId = addOptimisticNodeLocally(payload);
+      const originalSplitEdge = edgesRef.current.find(
+        (edge) =>
+          edge.id === splitEdgeId &&
+          edge.className !== "temp" &&
+          !isOptimisticEdgeId(edge.id),
+      );
+
+      const optimisticNodeId = addOptimisticNodeLocally({
+        ...payload,
+        className: "canvas-edge-insert-enter",
+      });
       const splitApplied = applyEdgeSplitLocally({
         clientRequestId,
         splitEdgeId: payload.splitEdgeId,
@@ -1411,6 +1422,34 @@ export function useCanvasSyncEngine({
         positionY: payload.positionY,
       });
 
+      if (isSyncOnline) {
+        try {
+          const realId = await trackPendingNodeCreate(
+            clientRequestId,
+            createNodeWithEdgeSplitRaw({ ...payload }),
+          );
+          await remapOptimisticNodeLocally(clientRequestId, realId);
+          return realId;
+        } catch (error) {
+          removeOptimisticCreateLocally({
+            clientRequestId,
+            removeNode: true,
+            removeEdge: true,
+          });
+
+          if (splitApplied && originalSplitEdge) {
+            setEdges((current) => {
+              if (current.some((edge) => edge.id === originalSplitEdge.id)) {
+                return current;
+              }
+              return [...current, originalSplitEdge];
+            });
+          }
+
+          throw error;
+        }
+      }
+
       if (splitApplied) {
         await enqueueSyncMutation("createNodeWithEdgeSplit", payload);
       } else {
@@ -1430,7 +1469,19 @@ export function useCanvasSyncEngine({
 
       return optimisticNodeId;
     },
-    [addOptimisticNodeLocally, applyEdgeSplitLocally, createNodeWithEdgeSplitMut, enqueueSyncMutation, isSyncOnline],
+    [
+      addOptimisticNodeLocally,
+      applyEdgeSplitLocally,
+      controller.pendingConnectionCreatesRef,
+      createNodeWithEdgeSplitRaw,
+      edgesRef,
+      enqueueSyncMutation,
+      isSyncOnline,
+      remapOptimisticNodeLocally,
+      removeOptimisticCreateLocally,
+      setEdges,
+      trackPendingNodeCreate,
+    ],
   );
 
   const runBatchRemoveNodesMutation = useCallback<RunBatchRemoveNodesMutation>(