Convert string to camel case

[RazvanBugoi]

https://www.codewars.com/kata/517abf86da9663f1d2000003/train/javascript

[RazvanBugoi]

function toCamelCase(str){
  let arr;
  let output = ""

  if (str.includes("-")) {
    arr = str.split("-") 
  } else if (str.includes("_")) {
    arr = str.split("_") 
  } else {
    return str
  }

  arr.forEach((element) => output += element.replace(element[0], element[0].toUpperCase()))
  return str[0].toLowerCase() == str[0] ? output.replace(output[0], output[0].toLowerCase()) : output
}