const accum = (s, result = '') => {
result += s[0].toUpperCase() + '-'
for (let i = 1; i < s.length - 1; i += 1) {
result += s[i].toLowerCase().repeat(i + 1) + '-'
}
result += s[s.length - 1].toLowerCase().repeat(s.length - 1)
return result
}
accum("AbCd")