vue loading indicator?

HTML

<script src='https://api.tiles.mapbox.com/mapbox-gl-js/v0.51.0/mapbox-gl.js'></script>

<link href='https://api.tiles.mapbox.com/mapbox-gl-js/v0.51.0/mapbox-gl.css' rel='stylesheet' />

<div id='map'></div>

CSS

body { margin:0; padding:0; }
        #map { position:absolute; top:0; bottom:0; width:100%; }

Vue

mapboxgl.accessToken = 'pk.eyJ1Ijoid2F5enVwIiwiYSI6ImNpZ2RqZDJkZzA4MWZ2M2x0ZjkyeDVoeDMifQ.kKh_ufcY770308Dfktqlxw';

var map = new mapboxgl.Map({
    container: 'map', // container id
    style: 'mapbox://styles/mapbox/light-v9', //stylesheet location
    center: [2.2, 48.7], // starting position
    zoom: 13 // starting zoom
});

map.addControl(new mapboxgl.FullscreenControl());