Rev parentheses

function solution(inputString) {
//For single level depth
let stack=[];
let final=inputString.split(''), left,right;
for(let x=0; x<inputString.length; x++){
    
    if(inputString[x]=="("){
        stack.push(x);
    }
    
    else if(inputString[x]==")"){
        left=stack.pop()+1;
        right=x-1;
        
        while(left < right){
            let temp=final[left];
            final[left]=final[right];
            final[right]=temp;
            left++;
            right--;
        }
        
    }
    
    // else{
        
    //     if(stack.length==0){
    //     final+=inputString[x];
    // }
    
    }
    return final.filter(x=>x.match(/[a-z]/i)).join('')

}

console.log(solution("(abc(tzx(yz)))"))