const s1 = "abcabcbb";
const s2 = "bbbbb";
const s3 = "pwwkew";
const s4 = "abcdefg";


const checkIfCharExist = (str, char) => {
    let repeat = false
  for(val of str){
      if(val === char){
          return true
      }
  }
    return repeat 
}

const longestUniqueSubstring = (s) => {
     let arrOfSubStr = []
    for(track = 0; track < s.length ; track++){
       let str = s[track]
        
        for(trackNext = track + 1; trackNext < s.length; trackNext++ ){
            if(checkIfCharExist(str, s[trackNext])){
                break;
            }else{
                str = str + s[trackNext]
            }
        }
        console.log(arrOfSubStr)
        arrOfSubStr.push(str)
        str = ""
    }
    
    let longest = ""
    arrOfSubStr.forEach(item=>{
        if(item.length > longest.length){
            longest = item
        }
    })
    return longest
}

console.log(longestUniqueSubstring(s1)); // Output: 3 (substring "abc")
//console.log(longestUniqueSubstring(s2)); // Output: 1 (substring "b")
//console.log(longestUniqueSubstring(s3)); // Output: 3 (substring "wke")
//console.log(longestUniqueSubstring(s4));