Function mountReducer

docs/index.js:24722–24750

(reducer, initialArg, init)

      return "function" === typeof action ? action(state) : action;
    }
    function mountReducer(reducer, initialArg, init) {
      var hook = mountWorkInProgressHook();
      if (void 0 !== init) {
        var initialState = init(initialArg);
        if (shouldDoubleInvokeUserFnsInHooksDEV) {
          setIsStrictModeForDevtools(!0);
          try {
            init(initialArg);
          } finally {
            setIsStrictModeForDevtools(!1);
          }
        }
      } else initialState = initialArg;
      hook.memoizedState = hook.baseState = initialState;
      reducer = {
        pending: null,
        lanes: 0,
        dispatch: null,
        lastRenderedReducer: reducer,
        lastRenderedState: initialState
      };
      hook.queue = reducer;
      reducer = reducer.dispatch = dispatchReducerAction.bind(
        null,
        currentlyRenderingFiber$1,
        reducer
      );
      return [hook.memoizedState, reducer];
    }
    function updateReducer(reducer) {
      var hook = updateWorkInProgressHook();
      return updateReducerImpl(hook, currentHook, reducer);