Having trouble with the URL challenge

[Hozi625]

Hi all campers,

So I am having trouble with this challenge: Apply Functional Programming to Convert Strings to URL Slugs

So here’s what I am thinking:

function urlSlug(title) {
  let result = title.toLowerCase.trim().split(" ")
  for (let i = 0; i < result.length-1; i++){
    result[i].concat("-")
  }
  result.join("")
  return result
}
console.log(urlSlug("Winter Is Coming"))

I did the following:

1. All to lowercase and get rid of spaces
2. Split the string into array of words
3. I loop over every word in the array and concat every word with a - except for the last word
4. I join them into a single string

However, the result I have is
[ 'winter', 'is', 'coming' ]

I am pretty confused, I know theres some minor mistakes as I’ve already look through the answer, but why is my result still an array of words instead of a single string?

Thank you in advance

[JeremyLT]

Join does not mutate the array. You’ll need to capture the output of join.