JSFiddle - React, Tailwind, and code Playground

JavaScript

function sym(args) {
  arr0=arguments[0];
  arr1=arguments[1];
  arrNew=[];
  for (i=0;i<arr0.length;i++){
    for (ii=0;ii<arr1.length;ii++){
      if (arr0.indexOf(arr1[ii])<0){
        console.log(arr1[ii]);
        if (arr1.indexOf(arr0[i])<0){
          console.log(arr0[i]);
        }
      }
    }
  }
  return arrNew;
}

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