vuex2 mapActions 报错 `unknown action type: xxxx`

export const setBreadCrumb = ({ dispatch }, data) => {

    dispatch('SET_BREADCRUMB', data)

}

当调用的时候报[vuex2] mapActions 报错 `unknown action type: setBreadCrumb`

后台改成 

export const setBreadCrumb = ({ commit }, data) => {

    commit('SET_BREADCRUMB', data)

}

未报错