var countries = [

    { label: 'Germany', value: 'DE' },

    { label: 'Austria', value: 'AU' }

];

​

var input = document.getElementById("country");

​

function getWord(s, pos) {

    const n = s.substring(pos).match(/^[a-zA-Z0-9-_]+/)

    const p = s.substring(0, pos).match(/[a-zA-Z0-9-_]+$/)

    if (!p && !n) return ''

    return (p || '') + (n || '')

}

​

​

autocomplete({

    minLength: 0,

    input: input,

    fetch: function(text, update) {

        text = getWord(text, input.selectionStart).toLowerCase();

        var suggestions = countries.filter(n => n.label.toLowerCase().startsWith(text))

        update(suggestions);

    },

    onSelect: function(item) {

        input.value = item.label;

    },

    click: function(e) { e.fetch(); }

});

​