<template>
  <div id="app">
    <img src="./assets/logo.png">
    <div v-show="showMessage">{{message}}</div>
    <router-view/>
  </div>
</template>
<script>
export default {
  name: 'App',
  data: () => {
    return {
      showMessage: true,
      message: 'Hello, World!'
    };
  }
};
</script>
...