When I try to add .concat(authMiddleware) below but “middleware” is underscore redline:

export const store = configureStore({
    reducer: {
        persistedReducer,
    },
    middleware: (getDefaultMiddleware) =>
        getDefaultMiddleware({
            serializableCheck: {
                ignoredActions: [FLUSH, REHYDRATE, PAUSE, PERSIST, PURGE, REGISTER],
            },
        }).concat(authMiddleware),
});

How do I fix it or use another idea to add middleware?