provide() {
    return {
      tb: () => this.data
    };
  },

inject: ["tb"],
computed: {
    list() {
      return this.tb();
    }
},
watch: {
    list: {
      deep: true,
      handler(e) {
        console.log("watch", e);
      }
    }
},

方案来自：Vue.js中provide/inject实现响应式数据更新