Can this be done with a for loop?

JavaScript
1

Objective: for an input string such as “ThisIsAnExample” the function should return “This-Is-An-Example”

I have this so far

function addHyphen(str) {

 for(let i = 1 ; i<str.length ; i++) {
   if (str[i] == str[i].toUpperCase()) {
     var str2 = str.slice(0,i) + "-" +str.slice(i)
   }
 }
  
}

Of course, console logging this gives:

“This-IsAnExample”
“ThisIs-AnExample”
“ThisIsAn-Example”

So while the code does add a ‘-’ before each capital letter after the first, it does not ‘remember’ each one as the value of str2 gets reassigned

2

Short version: Yes, yes you can.

You don’t need str2. You can assign the changes to your str variable (str = str.slice(0,i) + "-" +str.slice(i)). Since your str variable will get longer when that happens, and since you need to make sure you skip your newly created -, you’ll want to increase your iterator variable (i) by 1 if you add a dash. Then you can just return str.

2 Likes
3

@mcaubrey’s suggestion is great. If you want to continue with your current logic with a small modification, you could do:

function addHyphen(str) {
  let currentWordIndex = 0; // keeps track of start of each word before next hyphen
  let hypenatedStr = ""; // used to build final string
  for (let i = 1; i < str.length; i++) {
    if (str[i] == str[i].toUpperCase()) {
      hypenatedStr += str.slice(currentWordIndex, i) + "-"
      currentWordIndex = i;
    }
  }
  return hypenatedStr + str.slice(currentWordIndex); // concatenates the last word
}
4

I feel like this would be a simpler way to appropriate their current code (following what I wrote here).

function addHyphen(str) {
    for(let i = 1 ; i<str.length ; i++) {
        if (str[i] == str[i].toUpperCase()) {
            str = str.slice(0,i) + "-" +str.slice(i); i++;
        }
    }
    return str;
}
5

@mcaubrey Sure, that is nice. I would remove the extra i++; and just have:

str = str.slice(0,i) + "-" +str.slice(i++);
6