feat(edgeUpdate): add onEdgeUpdateStart handler closes #1120

src/container/ReactFlow/index.tsx

@@ -115,6 +115,7 @@ export interface ReactFlowProps extends Omit<HTMLAttributes<HTMLDivElement>, 'on
   onEdgeMouseMove?: (event: MouseEvent, edge: Edge) => void;
   onEdgeMouseLeave?: (event: MouseEvent, edge: Edge) => void;
   onEdgeDoubleClick?: (event: MouseEvent, edge: Edge) => void;
+  onEdgeUpdateStart?: (event: MouseEvent, edge: Edge) => void;
   edgeUpdaterRadius?: number;
   nodeTypesId?: string;
   edgeTypesId?: string;
@@ -192,6 +193,7 @@ const ReactFlow = forwardRef<ReactFlowRefType, ReactFlowProps>(
       onEdgeMouseEnter,
       onEdgeMouseMove,
       onEdgeMouseLeave,
+      onEdgeUpdateStart,
       edgeUpdaterRadius = 10,
       nodeTypesId = '1',
       edgeTypesId = '1',
@@ -270,6 +272,7 @@ const ReactFlow = forwardRef<ReactFlowRefType, ReactFlowProps>(
             onEdgeMouseEnter={onEdgeMouseEnter}
             onEdgeMouseMove={onEdgeMouseMove}
             onEdgeMouseLeave={onEdgeMouseLeave}
+            onEdgeUpdateStart={onEdgeUpdateStart}
             edgeUpdaterRadius={edgeUpdaterRadius}
           />
           <ElementUpdater elements={elements} />