Function useReducer

packages/react-debug-tools/src/ReactDebugHooks.js:302–323

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

}

function useReducer<S, I, A>(
  reducer: (S, A) => S,
  initialArg: I,
  init?: I => S,
): [S, Dispatch<A>] {
  const hook = nextHook();
  let state;
  if (hook !== null) {
    state = hook.memoizedState;
  } else {
    state = init !== undefined ? init(initialArg) : ((initialArg: any): S);
  }
  hookLog.push({
    displayName: null,
    primitive: class="st">'Reducer',
    stackError: new Error(),
    value: state,
    debugInfo: null,
    dispatcherHookName: class="st">'Reducer',
  });
  return [state, (action: A) => {}];
}

function useRef<T>(initialValue: T): {current: T} {
  const hook = nextHook();