implemented new fitView logic

packages/react/src/hooks/useConnection.ts

@@ -24,9 +24,32 @@ function getSelector<NodeType extends Node = Node, SelectorReturn = ConnectionSt
   return storeSelector;
 }
 /**
- * Hook for accessing the connection state.
+ * The `useConnection` hook returns the current connection when there is an active
+ * connection interaction. If no connection interaction is active, it returns null
+ * for every property. A typical use case for this hook is to colorize handles
+ * based on a certain condition (e.g. if the connection is valid or not).
  *
  * @public
+ * @param connectionSelector - An optional selector function used to extract a slice of the
+ * `ConnectionState` data. Using a selector can prevent component re-renders where data you don't
+ * otherwise care about might change. If a selector is not provided, the entire `ConnectionState`
+ * object is returned unchanged.
+ * @example
+ *
+ * ```tsx
+ *import { useConnection } from '@xyflow/react';
+ *
+ *function App() {
+ *  const connection = useConnection();
+ *
+ *  return (
+ *    <div> {connection ? `Someone is trying to make a connection from ${connection.fromNode} to this one.` : 'There are currently no incoming connections!'}
+ *
+ *   </div>
+ *   );
+ * }
+ * ```
+ *
  * @returns ConnectionState
  */
 export function useConnection<NodeType extends Node = Node, SelectorReturn = ConnectionState<InternalNode<NodeType>>>(