mpvue-dev-temp/src/store/modules/nav.js

export default {
  state: {
    channelId: 'rec'
  },
  getters: {
    channelId (state) {
      return state.channelId
    }
  },
  mutations: {
    CHANGE_CHANNEL_ID (state, channelId) {
      state.channelId = channelId
    }
  },
  actions: {
    changeChannelId ({ commit }, channelId) {
      commit('CHANGE_CHANNEL_ID', channelId)
    }
  }
}