vue中watch监听器的触发时机(watch的坑及解决)

 created() {
    this.typeId = this.$route.params.id;
    console.log("this.typeId的值发生改变，触发watch");
  },
  mounted() {
    console.log(this.typeUrl, "mounted中的typeUrl的值");
    //访问接口的函数
    this.getData();
  },

  watch: {
  // 监听订单类型 给出对应面包屑
  typeId: function (val) {
    if (val == 1) {
      console.log("watch触发了");
      this.selfBreadcrumb[1].name = "核销订单";
      this.typeUrl = "settlements";
      console.log(this.typeUrl, "这里是watch");
    } else if (val == 2) {
      this.selfBreadcrumb[1].name = "物流订单";
      this.typeUrl = "loGIStics-orders";
    } else if (val == 4) {
      this.selfBreadcrumb[1].name = "外卖订单";
      this.typeUrl = "takeout-orders";
    }
  },

var vm = new Vue({
  data: {
    a: 1,
    b: 2
  },
  watch: {
    a: function (val, oldVal) {
      console.log('new: %s, old: %s', val, oldVal)
    },
    // 方法名
    b: 'someMethod',
    // 选项的对象
    c: {
      handler: function (val, oldVal) {  },
      deep: true，
      immediate: true
    }
  }
})