Question about Intermediate Solution for Search and Replace Challenge

1

Hello. I wondered if the following solution contains unnecessary code (Line 2). The solution is shown on freeCodeCamp Algorithm Challenge Guide: Search and Replace. (2nd solution down).

function myReplace(str, before, after) {
//Create a regular expression object
  var re = new RegExp(before,"gi");
//Check whether the first letter is uppercase or not
  if(/[A-Z]/.test(before[0])){
  //Change the word to be capitalized
    after = after.charAt(0).toUpperCase()+after.slice(1);
     }
     //Replace the original word with new one
  var  newStr =  str.replace(re,after);

 return newStr;
}
// test here
myReplace("A quick brown fox jumped over the lazy dog", "jumped", "leaped");

What is var re = new RegExp(before,"gi"); 's role in the function? Thanks!

2

Could I just as well write the code without line 2, so it looks like this:

function myReplace(str, before, after) {
//Check whether the first letter is uppercase or not
  if(/[A-Z]/.test(before[0])){
  //Change the word to be capitalized
    after = after.charAt(0).toUpperCase()+after.slice(1);
     }
     //Replace the original word with new one
  var  newStr =  str.replace(before,after);

 return newStr;
}

// test here
myReplace("A quick brown fox jumped over the lazy dog", "jumped", "leaped");

Thanks!

3

I found the answer here : https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp

Basically, a regexp is being created and passed to re. The first parameter of the new regexp function is the pattern you are looking for. In this case it’s before = “jumped”. The second parameter are the “g” flag which means find all that match “jumped” the “i” flag is saying ignore case, so look for both upper and lower case.

4

My First Algorithm Worked. Its Easy To Understand: -

function myReplace(str, before, after) {

  if (before[0].match(/^[A-Z]/)){

  var af= after.replace(after[0], after[0].toUpperCase());

  }

  else {

  var af = after.replace(after[0], after[0].toLowerCase());

   }

  return str.replace(before, af);

}

myReplace("A quick brown fox jumped over the lazy dog", "jumped", "leaped");
5

Your code has been blurred out to avoid spoiling a full working solution for other campers who may not yet want to see a complete solution. In the future, if you post a full passing solution to a challenge and have questions about it, please surround it with [spoiler] and [/spoiler] tags on the line above and below your solution code.

Also, please do not revive 3 year old threads just to post your solution.

Thank you.