mutations是在一个独立的js文件里面 直接使用this.$set更新state对象数据会报错this.$set is not a function 这种情况怎么办呢？

state里面的数据

articleList: [
    {
      userinfo: {image: 'static/img/3.jpeg', nickname: 'eee', text: '嘿嘿', time: '十天前'},
      content: {href: '2222222', text: 'test', create_time: '', updata_time: ''},
      pic: [{path: 'static/img/0.jpg'}, {path: 'static/img/0.jpg'}, {path: 'static/img/0.jpg'}],
      likebar: {hot: 555, status: false, comments: 666},
      isFollow: true
    }
  ]

组件中触发action
this.$store.dispatch('getLists')

action.js

getLists (val) {
    api.articleList().then((res) => {
      val.commit('updateList', res)
    })
}

mutations.js

updateList (state, data) {
    this.$set(this.state.articleList, 0, data)  //这样写不对
    this.state.articleList = data //这样写视图不更新
}