function solution(new_id) {
let answer = new_id
.toLowerCase()
.replace(/[^\.a-z0-9-_]/g, "")
.replace(/\.+/g, ".")
.replace(/^\.|\.+$/, "")
if (answer === "") answer = "a"
answer = answer.slice(0, 15).replace(/\.+$/, "")
return answer.length > 2
? answer
: answer.padEnd(3, answer[answer.length - 1])
}
console.log(solution("...!@BaT#*..y.abcdefghijklm"))