var email = "joe_awesome@example.com";
function formatEmail(emilString){
    var splitEmail = emilString.split("@")
    var domain = splitEmail[1];
    var name = splitEmail[0];
    return  name.substring(0,3).concat("*********@").concat(domain)
}
console.log(formatEmail(email));



function formatEmailSameLength(emilString){
    var splitEmail = emilString.split("@")
    var domain = splitEmail[1];
    var name = splitEmail[0];
    return  name.substring(0,3).concat(Array(name.length-3).join("*")).concat("@").concat(domain)
}