javascript - 在 vuex mapState 中访问 vue 方法

Question

在 vuex mapState 中计算数据时，我有一项重要任务要做。每次数据更改时，我都需要调用此 vue 方法 countAlerts；为此，计算属性需要调用该方法，但是 this 作用域在使用 insight vuex mapState 时没有 vue 方法。

export default {
  name: "Alerts",
  methods: {
    countAlerts(data, period) {
      /// DO SOMETHING, THEN RETURN DATA
      return data;
    }
  },
  computed: {
    ...mapState({
      foundation: state => state.insights.foundation,
      insights: state => {
        return state.insights.list.filter(al => {
          switch (state.insights.foundation.period) {
            case "daily":
               // ====>> NEED TO CALL METHOD HERE <<=====
              al = this.countAlerts(al, "daily");
              if (
                al.threeDayUp ||
                al.threeDayDown ||
                al.greatDayUp ||
                al.greatDayDown
              ) {
                return al;
              }
              break;
            ///  MORE CODE ABOVE
          }
        });
      }
    })
  }
};

Answer 1

当您将计算属性定义为函数时，

this 会绑定(bind)到组件的上下文。

来自docs :

// to access local state with `this`, a normal function must be used
countPlusLocalState (state) {
  return state.count + this.localCount
}