Javascript algorithms

symmetric_difference.js

/*
  Symmetric difference of two sets is the set of elements
  which are in either of the two sets but not in both.

  e.g.
    symmetric_difference([1, 2, 3], [5, 2, 1, 4])
    // [3, 5, 4]
*/

function symmetric_difference(...args) {
// logic:
// 1. remove duplicates from each input array
// 2. loop through each elem of each input array
//    2.1. if elem does not exist in output array, push elem into output array
//    2.2. if elem does exist in output array, remove elem from output arra

  let result = args.reduce((prev, curr) => {
    curr = curr.filter((elem, index, arr) => arr.indexOf(elem) === index)
    for (let elem of curr){
      if (!prev.includes(elem)){
        prev.push(elem)
      } else {
        prev = prev.filter(x => x !== elem) 
      }
    }

    return prev
  }, [])

  return result
}