Problem updating Vuex status

Hi, I have the following problem, I am updating the state from one component and showing the contents of this variable in another, in the component that executes the commit the status changes but in the component that shows the information is not updated.

  state: {
    message: 'Message test'
  }      
  newMessage (state) {
    state.message = new Date()
  }      
  changeMessage ({commit}) {
    commit('newMessage')
  }
// Este es el componente que debe mostrar cuando cambio el estado
  div {{message}}
  import { mapState } from 'vuex'
  export default {
    computed: {
      ...mapState({
        message: state => state.message
      }),
    }
  }