Find the Symmetric Difference Feedback

Code Feedback
1

Hello, I’ve just solved the symmetric difference challenge (hope to contribute to the collection of all possible solutions) and would love to have some feedback on how I can make the code more readable, or if there is a more elegant way for the solution. Thank you!

function sym(...args) {
  let arr1 = []  // This will hold our accumulated result
  
  for (let i = 0; i < args.length-1; i++) {
    if (i == 0) {
      let unique1 = [...new Set(args[i])]
      let unique2 = [...new Set(args[i+1])]
      // Compare args[0] and args[1]
      for (let j = unique1.length-1; j >= 0; j--) {
        for (let k = unique2.length-1; k >= 0; k--) {
          if (unique1[j] == unique2[k]) {
            unique1.splice(j, 1)
            unique2.splice(k, 1)
          }
        }
      }
      let arr = new Set(unique1.concat(unique2))
      arr1 = [...arr]  // update outer variable
    } else {
      let unique2 = [...new Set(args[i+1])]
      for (let j = arr1.length-1; j >= 0; j--) {
        for (let k = unique2.length-1; k >= 0; k--) {
          if (arr1[j] == unique2[k]) {
            arr1.splice(j, 1)
            unique2.splice(k, 1)
          }
        }
      }
      let arr = new Set(arr1.concat(unique2))
      arr1 = [...arr]
    } 
  }
  console.log(arr1)
  return arr1;
}

sym([1, 1, 2, 5], [2, 2, 3, 5], [3, 4, 5, 5]);
2

hello and welcome to fcc forum :slight_smile:

well done :clap: , btw, is this some thing from fcc curriculum? if so then adding that link would be very useful and recommended…

  • what does this snippet does? as in reason behind it you are comparing them
  • this snippet seems to be a good candidate for DRY concept in that function

happy coding :slight_smile:

3

Few comments:

  • Naming things, if ie. arr1 needs comment to explain what it contains, it could use better name.
  • Using splice and changing length of both arrays when they are being iterated over. This could be very tricky to debug if something would not work as intended.
  • Is it really needed to have separate code handling i == 0 and different values of i?
  • Using Set to remove duplicates. This wasn’t really forbidden, but it’s simplifying part of the task. Task, which is to reproduce other feature of sets, so… :face_with_tongue:
  • Could be a personal preference, but usually I find (let j = 0; j < arr1.length; j++) much easier to read, instead of(let j = unique1.length-1; j >= 0; j--). Note: it will not work when using splice and changing length of array that’s being iterated over.