Vue アプリケーションで vue-router を使用するときに「TypeError: Cannot read property 'yyy' of null」という問題を解決するにはどうすればよいですか?

<template>
  <div>
    <h1>{{title}}</h1>
  </div>
</template>

<script>
export default {
  name: 'Article',
  props: {
    title: String,
  },
};
</script>

const routes = [
  {
    path: '/article/:id',
    name: 'Article',
    component: Article,
    props: true,
  }
]

// Event Bus.js
import Vue from 'vue';
export const EventBus = new Vue();

// Component 1.js
import { EventBus } from './Event Bus.js';
export default {
  name: 'Component1',
  created: function() {
    EventBus.$on('event-name', this.handleEvent);
  },
  methods: {
    handleEvent: function(data) {
      console.log('Received data:', data);
    },
  }
};

// Component 2.js
import { EventBus } from './Event Bus.js';
export default {
  name: 'Component2',
  created: function() {
    EventBus.$emit('event-name', 'Hello World');
  },
};

// store.js
import Vue from 'vue';
import Vuex from 'vuex';
Vue.use(Vuex);

const store = new Vuex.Store({
  state: {
    message: 'Hello World',
  },
  mutations: {
    setMessage: (state, payload) => {
      state.message = payload;
    },
  },
  actions: {
    updateMessage: ({commit}, payload) => {
      commit('setMessage', payload);
    },
  }
});

export default store;

// Component 1.js
import { mapState } from 'vuex';
export default {
  name: 'Component1',
  computed: {
    ...mapState(['message']),
  },
};

// Component 2.js
import { mapActions } from 'vuex';
export default {
  name: 'Component2',
  methods: {
    ...mapActions(['updateMessage']),
    handleClick: function() {
      this.updateMessage('Updated Message');
    },
  },
};

<template>
  <div>
    <component-a v-if="isComponentAActive"></component-a>
    <component-b v-else></component-b>
  </div>
</template>

<script>
import ComponentA from './ComponentA.vue';
import ComponentB from './ComponentB.vue';

export default {
  name: 'App',
  components: {
    ComponentA,
    ComponentB,
  },
  data: function() {
    return {
      isComponentAActive: true,
    };
  },
};
</script>