map-snippet-2.js

// Wait for load
map.on('load', () => {
    axios.get('https://gist.githubusercontent.com/rozklad/49d5ca8a7fbd0173e191820994448690/raw/3c2c1b230b6e32f7fba4848a9fba95465d5d90b1/migration-1990-2017.json')
        .then((response) => {
            // Store response in geoData
            geoData = response.data;

            // Base layer with countries data
            map.addLayer({
                id: 'countries',
                source: {
                    type: 'geojson',
                    data: response.data,
                },
                type: 'fill',
                paint: {
                    'fill-color': '#3B8C9B',
                    'fill-opacity': 1,
                    'fill-outline-color': '#0a0a0a',
                },
            });

            // Hovering over countries
            map.addLayer({
                id: 'countries-hovered',
                source: {
                    type: 'geojson',
                    data: response.data,
                },
                type: 'fill',
                paint: {
                    'fill-color': '#3B8C9B',
                    'fill-opacity': 1,
                    'fill-outline-color': '#0a0a0a',
                },
                filter: ['in', 'name', ''],
            });

        });
});