The context of this not provided to the modules exporting

Question

I'm displeased with the formulation of the question. Feel encouraged to suggest an improvement. Also, please keep in mind that due to ignoyance (ignorance leading to annoyance), I might have flawed diagnostics of hte issue. Sorry about that.

In this answer it's suggested to use this.$store.xxx and it fails in my code because this is undefined. I strongly suspect something stupid being done by the author of the code (that would be me), so I'll present the schematics of my component layout.

The way it's intended is that I have a landing page index.js that creates two components - one for the visuals of the application and one for the storage of information. The visual App will consist of a navigation bar (and a rendering area later on). The navbar will dispatch commands to the store (and to the viewing area) rendering different *.vue files showing tables, lists etc.

So, how come I get to see the text this is undefined? Is my structure entirely flawed or am I just missing a small detail here and there?

index.js

import Vue from "vue"
import Store from "./vuex_app/store"
import App from "./vuex_modules/app.vue"
new Vue({ el: "#app-base", components: { App }, store: Store });

store.js

import Vue from "vue";
import Vuex from "vuex";
Vue.use(Vuex);
const state = { ... };
const mutations = { ... };
export default new Vuex.Store({ state, mutations });

app.vue

<template><div id="app">App component<navigation></navigation></div></template>
<script>
import navigation from "./navigation.vue"
export default { components: { navigation } }
</script>

navigation.vue

<template><div id="nav-bar"><p v-on:click="updateData">Update</p></div></template>
<script>
import { updateData } from "../vuex_app/actions";
export default {
  vuex: {
    actions: { updateData },
    getters: { ... }
  },
  methods: {
    updateData: () => { 
      console.log("this is " + this);
      this.$store.dispatch("updateData");
    }
  }
}
</script>

actions.js

export const updateData = ({dispatch}, data) => { 
  console.log("invoked updateData"); 
  dispatch("UPDATE_DATA", data); 
};

Answer 1

Vue.js offers a pretty nice reactive type, minimalist JavaScript framework. Unfortunately, per this link there may be some unusual usage requirements. In this case,

Don’t use arrow functions on an instance property or callback (e.g. vm.$watch('a', newVal => this.myMethod())). As arrow functions are bound to the parent context, this will not be the Vue instance as you’d expect and this.myMethod will be undefined.