Convert camelCased string into snaked_string.

snaked_word.js

let convertToSnake = (camelCased) => {
    let lettersArr = [...camelCased];
    let snaked_str = '';
    lettersArr.forEach(letter => {
      if(letter !== letter.toUpperCase()){
        snaked_str += letter
      } else {
        snaked_str += `_${letter.toLowerCase()}`
      }
    })
    return snaked_str;
}