https://www.codewars.com/kata/mumbling/
This time no story, no theory. The examples below show you how to write function accum:
Examples:
accum('abcd'); // "A-Bb-Ccc-Dddd"
accum('RqaEzty'); // "R-Qq-Aaa-Eeee-Zzzzz-Tttttt-Yyyyyyy"
accum('cwAt'); // "C-Ww-Aaa-Tttt"The parameter of accum is a string which includes only letters from a..z and A..Z.