hyphenate

let str = "hello world"
let arr=str.split('')
let newarr=[];
let vowels =['a', 'e', 'i', 'o', 'u'
]

for(let i=0; i<arr.length; i++){
   if(!(vowels.includes(arr[i])) && !(vowels.includes(arr[i+1]))){
         newarr.push(arr[i])
         newarr.push('-')
      }
  else 
    newarr.push(arr[i])
}


if(newarr[newarr.length-1] === "-") 
   newarr.pop()
console.log(newarr.join(''))