feat(wrapper): add onSelectionChange handler

README.md

@@ -72,6 +72,7 @@ const BasicFlow = () => (
 - `onConnect`: connect handler
 - `onLoad`: editor load handler
 - `onMove`: move handler
+- `onSelectionChange`: fired when element selection changes
 - `nodeTypes`: object with [node types](#node-types--custom-nodes)
 - `edgeTypes`: object with [edge types](#edge-types--custom-edges)
 - `style`: css style passed to the wrapper

example/src/Overview/index.js

@@ -5,6 +5,7 @@ import ReactFlow, { removeElements, addEdge, MiniMap, Controls } from 'react-flo
 const onNodeDragStart = node => console.log('drag start', node);
 const onNodeDragStop = node => console.log('drag stop', node);
 const onElementClick = element => console.log('click', element);
+const onSelectionChange = elements => console.log('selection change', elements);
 const onLoad = (graph) => {
   console.log('graph loaded:', graph);
   graph.fitView();
@@ -53,6 +54,7 @@ const OverviewFlow = () => {
       onConnect={onConnect}
       onNodeDragStart={onNodeDragStart}
       onNodeDragStop={onNodeDragStop}
+      onSelectionChange={onSelectionChange}
       style={{ width: '100%', height: '100%' }}
       onLoad={onLoad}
       connectionLineStyle={{ stroke: '#ddd', strokeWidth: 2 }}

src/components/NodesSelection/index.tsx

@@ -50,9 +50,11 @@ export default memo(() => {
     };
     const offsetX: number = scaledClient.x - position.x - tx;
     const offsetY: number = scaledClient.y - position.y - ty;
-    const selectedNodes = (state.selectedElements.filter(isNode) as Node[]).map(
-      (selectedNode) => state.nodes.find((node) => node.id === selectedNode.id)! as Node
-    );
+    const selectedNodes = state.selectedElements
+      ? (state.selectedElements.filter(isNode) as Node[]).map(
+          (selectedNode) => state.nodes.find((node) => node.id === selectedNode.id)! as Node
+        )
+      : [];
 
     const nextStartPositions = getStartPositions(selectedNodes);
 
@@ -68,14 +70,16 @@ export default memo(() => {
       y: evt.clientY / tScale,
     };
 
-    (state.selectedElements.filter(isNode) as Node[]).forEach((node) => {
-      const pos: XYPosition = {
-        x: startPositions[node.id].x + scaledClient.x - position.x - offset.x - tx,
-        y: startPositions[node.id].y + scaledClient.y - position.y - offset.y - ty,
-      };
+    if (state.selectedElements) {
+      (state.selectedElements.filter(isNode) as Node[]).forEach((node) => {
+        const pos: XYPosition = {
+          x: startPositions[node.id].x + scaledClient.x - position.x - offset.x - tx,
+          y: startPositions[node.id].y + scaledClient.y - position.y - offset.y - ty,
+        };
 
-      updateNodePos({ id: node.id, pos });
-    });
+        updateNodePos({ id: node.id, pos });
+      });
+    }
   };
 
   return (

src/components/SelectionListener/index.ts

@@ -0,0 +1,22 @@
+import { useEffect } from 'react';
+
+import { Elements } from '../../types';
+import { useStoreState } from '../../store/hooks';
+
+interface SelectionListenerProps {
+  onSelectionChange: (elements: Elements | null) => void;
+}
+
+// This is just a helper component for calling the onSelectionChange listener.
+// As soon as easy-peasy has implemented the effectOn hook, we can remove this compeonent
+// and use the hook instead. https://github.com/ctrlplusb/easy-peasy/pull/459
+
+export default ({ onSelectionChange }: SelectionListenerProps) => {
+  const selectedElements = useStoreState((s) => s.selectedElements);
+
+  useEffect(() => {
+    onSelectionChange(selectedElements);
+  }, [selectedElements]);
+
+  return null;
+};

src/container/EdgeRenderer/index.tsx

@@ -117,7 +117,7 @@ function renderEdge(
   edge: Edge,
   props: EdgeRendererProps,
   nodes: Node[],
-  selectedElements: Elements,
+  selectedElements: Elements | null,
   isInteractive: boolean
 ) {
   const [sourceId, sourceHandleId] = edge.source.split('__');
@@ -154,9 +154,9 @@ function renderEdge(
     targetPosition
   );
 
-  const isSelected = (selectedElements as Edge[]).some(
-    (elm) => isEdge(elm) && elm.source === sourceId && elm.target === targetId
-  );
+  const isSelected = selectedElements
+    ? (selectedElements as Edge[]).some((elm) => isEdge(elm) && elm.source === sourceId && elm.target === targetId)
+    : false;
 
   return (
     <EdgeComponent

src/container/NodeRenderer/index.tsx

@@ -16,7 +16,7 @@ function renderNode(
   node: Node,
   props: NodeRendererProps,
   transform: Transform,
-  selectedElements: Elements,
+  selectedElements: Elements | null,
   isInteractive: boolean
 ) {
   const nodeType = node.type || 'default';
@@ -25,7 +25,7 @@ function renderNode(
     console.warn(`No node type found for type "${nodeType}". Using fallback type "default".`);
   }
 
-  const isSelected = selectedElements.some(({ id }) => id === node.id);
+  const isSelected = selectedElements ? selectedElements.some(({ id }) => id === node.id) : false;
 
   return (
     <NodeComponent

src/container/ReactFlow/index.tsx

@@ -14,6 +14,7 @@ import DefaultNode from '../../components/Nodes/DefaultNode';
 import InputNode from '../../components/Nodes/InputNode';
 import OutputNode from '../../components/Nodes/OutputNode';
 import { createNodeTypes } from '../NodeRenderer/utils';
+import SelectionListener from '../../components/SelectionListener';
 import BezierEdge from '../../components/Edges/BezierEdge';
 import StraightEdge from '../../components/Edges/StraightEdge';
 import StepEdge from '../../components/Edges/StepEdge';
@@ -32,6 +33,7 @@ export interface ReactFlowProps extends Omit<HTMLAttributes<HTMLDivElement>, 'on
   onConnect: (connection: Edge | Connection) => void;
   onLoad: OnLoadFunc;
   onMove: () => void;
+  onSelectionChange: (elements: Elements | null) => void;
   nodeTypes: NodeTypesType;
   edgeTypes: EdgeTypesType;
   connectionLineType: string;
@@ -62,6 +64,7 @@ const ReactFlow = ({
   onConnect,
   onNodeDragStart,
   onNodeDragStop,
+  onSelectionChange,
   connectionLineType,
   connectionLineStyle,
   deleteKeyCode,
@@ -105,6 +108,7 @@ const ReactFlow = ({
           onlyRenderVisibleNodes={onlyRenderVisibleNodes}
           isInteractive={isInteractive}
         />
+        {onSelectionChange && <SelectionListener onSelectionChange={onSelectionChange} />}
         {children}
       </StoreProvider>
     </div>
@@ -143,7 +147,6 @@ ReactFlow.defaultProps = {
   snapGrid: [16, 16],
   onlyRenderVisibleNodes: true,
   isInteractive: true,
-  className: '',
 };
 
 export default ReactFlow;

src/hooks/useGlobalKeyHandler.ts

@@ -11,22 +11,19 @@ interface HookParams {
 }
 
 export default ({ deleteKeyCode, onElementsRemove }: HookParams): void => {
-  const state = useStoreState(s => ({
+  const state = useStoreState((s) => ({
     selectedElements: s.selectedElements,
     edges: s.edges,
   }));
-  const setNodesSelection = useStoreActions(a => a.setNodesSelection);
+  const setNodesSelection = useStoreActions((a) => a.setNodesSelection);
   const deleteKeyPressed = useKeyPress(deleteKeyCode);
 
   useEffect(() => {
-    if (deleteKeyPressed && state.selectedElements.length) {
+    if (deleteKeyPressed && state.selectedElements) {
       let elementsToRemove = state.selectedElements;
 
       // we also want to remove the edges if only one node is selected
-      if (
-        state.selectedElements.length === 1 &&
-        !isEdge(state.selectedElements[0])
-      ) {
+      if (state.selectedElements.length === 1 && !isEdge(state.selectedElements[0])) {
         const node = (state.selectedElements[0] as unknown) as Node;
         const connectedEdges = getConnectedEdges([node], state.edges);
         elementsToRemove = [...state.selectedElements, ...connectedEdges];

src/store/index.ts

@@ -56,7 +56,7 @@ export interface StoreModel {
   transform: Transform;
   nodes: Node[];
   edges: Edge[];
-  selectedElements: Elements;
+  selectedElements: Elements | null;
   selectedNodesBbox: Rect;
 
   d3Zoom: ZoomBehavior<Element, unknown> | null;
@@ -95,8 +95,6 @@ export interface StoreModel {
 
   setSelectedElements: Action<StoreModel, Elements | Node | Edge>;
 
-  updateSelection: Action<StoreModel, SelectionRect>;
-
   updateTransform: Action<StoreModel, TransformXYK>;
 
   updateSize: Action<StoreModel, Dimensions>;
@@ -122,7 +120,7 @@ const storeModel: StoreModel = {
   transform: [0, 0, 1],
   nodes: [],
   edges: [],
-  selectedElements: [],
+  selectedElements: null,
   selectedNodesBbox: { x: 0, y: 0, width: 0, height: 0 },
 
   d3Zoom: null,
@@ -250,8 +248,11 @@ const storeModel: StoreModel = {
     const selectedElementsUpdated = !isEqual(nextSelectedElements, state.selectedElements);
 
     state.selection = nextRect;
-    state.selectedElements = selectedElementsUpdated ? nextSelectedElements : state.selectedElements;
     state.userSelectionRect = nextRect;
+
+    if (selectedElementsUpdated) {
+      state.selectedElements = nextSelectedElements.length > 0 ? nextSelectedElements : null;
+    }
   }),
 
   unsetUserSelection: action((state) => {
@@ -261,7 +262,7 @@ const storeModel: StoreModel = {
       state.selectionActive = false;
       state.userSelectionRect = { ...state.userSelectionRect, draw: false };
       state.nodesSelectionActive = false;
-      state.selectedElements = [];
+      state.selectedElements = null;
 
       return;
     }
@@ -283,7 +284,7 @@ const storeModel: StoreModel = {
   setNodesSelection: action((state, { isActive, selection }) => {
     if (!isActive || typeof selection === 'undefined') {
       state.nodesSelectionActive = false;
-      state.selectedElements = [];
+      state.selectedElements = null;
 
       return;
     }
@@ -291,7 +292,7 @@ const storeModel: StoreModel = {
 
     if (!selectedNodes.length) {
       state.nodesSelectionActive = false;
-      state.selectedElements = [];
+      state.selectedElements = null;
 
       return;
     }
@@ -311,17 +312,6 @@ const storeModel: StoreModel = {
     state.selectedElements = selectedElements;
   }),
 
-  updateSelection: action((state, selection) => {
-    const selectedNodes = getNodesInside(state.nodes, selection, state.transform);
-    const selectedEdges = getConnectedEdges(selectedNodes, state.edges);
-
-    const nextSelectedElements = [...selectedNodes, ...selectedEdges];
-    const selectedElementsUpdated = !isEqual(nextSelectedElements, state.selectedElements);
-
-    state.selection = selection;
-    state.selectedElements = selectedElementsUpdated ? nextSelectedElements : state.selectedElements;
-  }),
-
   updateTransform: action((state, transform) => {
     state.transform = [transform.x, transform.y, transform.k];
   }),