Function useReducer

packages/react-reconciler/src/ReactFiberHooks.js:4076–4090

(
      reducer: (S, A) => S,
      initialArg: I,
      init?: I => S,
    )

      }
    },
    useReducer<S, I, A>(
      reducer: (S, A) => S,
      initialArg: I,
      init?: I => S,
    ): [S, Dispatch<A>] {
      currentHookNameInDev = 'useReducer';
      mountHookTypesDev();
      const prevDispatcher = ReactSharedInternals.H;
      ReactSharedInternals.H = InvalidNestedHooksDispatcherOnMountInDEV;
      try {
        return mountReducer(reducer, initialArg, init);
      } finally {
        ReactSharedInternals.H = prevDispatcher;
      }
    },
    useRef<T>(initialValue: T): {current: T} {
      currentHookNameInDev = 'useRef';
      mountHookTypesDev();