(async () => {

    const topology = await fetch(
        'https://code.highcharts.com/mapdata/custom/world.topo.json'
    ).then(response => response.json());

    Highcharts.getJSON('https://cdn.jsdelivr.net/gh/highcharts/[email protected]/samples/data/world-population-density.json', function (data) {

        // Prevent logarithmic errors in color calulcation
        data.forEach(function (p) {
            p.value = (p.value < 1 ? 1 : p.value);
        });

        // Initialize the chart
        Highcharts.mapChart('container', {

            chart: {
                map: topology
            },

            title: {
                text: 'Fixed tooltip with HTML'
            },

            legend: {
                title: {
                    text: 'Population density per km²',
                    style: {
                        color: ( // theme
                            Highcharts.defaultOptions &&
                            Highcharts.defaultOptions.legend &&
                            Highcharts.defaultOptions.legend.title &&
                            Highcharts.defaultOptions.legend.title.style &&
                            Highcharts.defaultOptions.legend.title.style.color
                        ) || 'black'
                    }
                }
            },

            mapNavigation: {
                enabled: true,
                buttonOptions: {
                    verticalAlign: 'bottom'
                }
            },

            tooltip: {
                backgroundColor: 'none',
                borderWidth: 0,
                shadow: false,
                useHTML: true,
                padding: 0,
                pointFormat: '<span class="f32"><span class="flag {point.properties.hc-key}">' +
                    '</span></span> {point.name}<br>' +
                    '<span style="font-size:30px">{point.value}/km²</span>',
                positioner: function () {
                    return { x: 0, y: 250 };
                }
            },

            colorAxis: {
                min: 1,
                max: 1000,
                type: 'logarithmic'
            },

            series: [{
                data: data,
                joinBy: ['iso-a3', 'code3'],
                name: 'Population density'
            }]
        });
    });

})();