[Vuejs]-Unknown Custom element laravel vue

You have some Blade syntax inside your template:

<div class="col-md col-md-12">
    @comments(['model'=>$book])
</div>

If this does not fix your problem than you might want to check when you load your app.js file or load the component locally for the Vue instance:

import comment from './components/Comment';

const app = new Vue({
    el: '#app',
    store,
    components: {
        comment
    }
});