string reverse excluding special char.

const reverseOnlyLetters = (val) => {
var arr = val.split('')
var revArr = []

arr.slice().reverse().forEach(val => {
if(isAlphabet(val)){
revArr.push(val)
}
})

arr.forEach((val, index) => {
  if(!isAlphabet(val)){
    //console.log('nc')
    revArr.splice(index, 0, val)
    //console.log(val)
    
  }

})

console.log(revArr.join(''))
}

function isAlphabet(val) {
//console.log(val)
if((val >= 'A' && val <= 'Z') || (val >= 'a' && val <= 'z')){
//console.log(true)
return true
}
else{ //console.log(false)
return false

}
}

var input = "ab-cdasd-!@#$hjh$hjhjh$kllk@"
reverseOnlyLetters(input)