JSFiddle - React, Tailwind, and code Playground

JavaScript

function sym() {
  var args = Array.prototype.slice.call(arguments);
  var flatArgs = args.reduce((a, b) => a.concat(b));
  return flatArgs.filter(function( arrayValue ){
  	j = 0;
  	for (var i = 0; i < arguments.length; i++) {
    	if ( args[i].indexOf( arrayValue ) == -1 ) {
      	j++;
        if ( j == arguments.length - 1 ) {
	      	return arrayValue;
        }
      }
    }
  });
}


alert(sym([1, 2, 3], [5, 2, 1, 4], [1, 5, 6, 7]));