utils.js

function getDateFormBithday(bday) {
    if(!bday){
        return null;
    }
    const [day,month] = bday.split(".");
    const date = new Date();
    date.setMonth(month-1);
    date.setDate(day);
    return date;
}
function getNameForCompare(friend) {
    let name='';
    if (friend.first_name){
        name+=friend.first_name;
    }
    if (friend.last_name){
        name+=friend.last_name;
    }
    return name;
}
export function sortByBDay(list) {
    return list.sort((a, b)=>{
        if(!a.bdate){
            return 1;
        }else if (!b.bdate){
            return -1;
        }

        const aDate = getDateFormBithday(a.bdate);
        const bDate= getDateFormBithday(b.bdate);
        return aDate-bDate;
    });
}

export function sortByName(list) {
    return list.sort((a,b)=>{
       const aName = getNameForCompare(a);
       const bName = getNameForCompare(b);
       return aName.localeCompare(bName);
    });
}