feat(react): Support Mutiple useOnSelectionChange Hook subscribers

examples/react/src/examples/UseOnSelectionChange/index.tsx

@@ -1,4 +1,4 @@
-import { useCallback } from 'react';
+import { useCallback, useState } from 'react';
 import  {
   ReactFlow,
   addEdge,
@@ -35,9 +35,9 @@ const initialEdges: Edge[] = [
   },
 ];
 
-const SelectionLogger = () => {
+const SelectionLogger = ({ id }: { id: string }) => {
   const onChange = useCallback(({ nodes, edges }: OnSelectionChangeParams) => {
-    console.log(nodes, edges);
+    console.log(id, nodes, edges);
   }, []);
 
   useOnSelectionChange({
@@ -63,14 +63,23 @@ const Flow = () => {
   );
 };
 
-const WrappedFlow = () => (
+const WrappedFlow = () => {
+  const [secondLoggerActive, setSecondLoggerActive] = useState<boolean>(false);
+
+  const toggleSecondLogger = () => {
+    setSecondLoggerActive(!secondLoggerActive);
+  };
+
+  return (
     <ReactFlowProvider>
       <Flow />
-    <SelectionLogger />
+      <SelectionLogger id="Logger 1" />
+      {secondLoggerActive && <SelectionLogger id="Logger 2" />}
       <div style={{ position: 'absolute', right: 10, top: 10, zIndex: 4 }}>
-      <input type={'text'} placeholder={'name'} />
+        <button onClick={toggleSecondLogger}>{secondLoggerActive ? 'Disable' : 'Enable'} Logger 2</button>
       </div>
     </ReactFlowProvider>
   );
+};
 
 export default WrappedFlow;

packages/react/src/components/SelectionListener/index.tsx

@@ -33,7 +33,7 @@ const SelectionListener = memo(({ onSelectionChange }: SelectionListenerProps) =
   useEffect(() => {
     const params = { nodes: selectedNodes, edges: selectedEdges };
     onSelectionChange?.(params);
-    store.getState().onSelectionChange?.(params);
+    store.getState().onSelectionChange.forEach((fn) => fn(params));
   }, [selectedNodes, selectedEdges, onSelectionChange]);
 
   return null;

packages/react/src/hooks/useOnSelectionChange.ts

@@ -4,14 +4,19 @@ import { useStoreApi } from './useStore';
 import type { OnSelectionChangeFunc } from '../types';
 
 export type UseOnSelectionChangeOptions = {
-  onChange?: OnSelectionChangeFunc;
+  onChange: OnSelectionChangeFunc;
 };
 
 function useOnSelectionChange({ onChange }: UseOnSelectionChangeOptions) {
   const store = useStoreApi();
 
   useEffect(() => {
-    store.setState({ onSelectionChange: onChange });
+    const addedOnSelectionChange = [...store.getState().onSelectionChange, onChange];
+    store.setState({ onSelectionChange: addedOnSelectionChange });
+    return () => {
+      const removedOnSelectionChange = store.getState().onSelectionChange.filter((fn) => fn !== onChange);
+      store.setState({ onSelectionChange: removedOnSelectionChange });
+    };
   }, [onChange]);
 }
 

packages/react/src/store/initialState.ts

@@ -92,6 +92,7 @@ const getInitialState = ({
     connectionRadius: 20,
     onError: () => null,
     isValidConnection: undefined,
+    onSelectionChange: [],
 
     lib: 'react',
   };

packages/react/src/types/store.ts

@@ -124,7 +124,7 @@ export type ReactFlowStore = {
   onViewportChange?: OnViewportChange;
   onViewportChangeEnd?: OnViewportChange;
   
-  onSelectionChange?: OnSelectionChangeFunc;
+  onSelectionChange: OnSelectionChangeFunc[];
 
   ariaLiveMessage: string;
   autoPanOnConnect: boolean;