JSFiddle - React, Tailwind, and code Playground

JavaScript

var args = Array.prototype.slice.call(arguments);

function deleteAll(arr,num) {
    
    arr=arr.filter(function(value){
    
        return (value!==num);
    
     });
  
     return arr;
  
}

function diff(arr1,arr2){
  
    for(var i=0;i<arr1.length;i++){
      
        for(var j=0;j<arr2.length;j++){
            
            if(arr1[i]===arr2[j]) {
                
                arr1=deleteAll(arr1,arr1[i]); 
                 i-=1;
     
             }
        } 
     }  
   
  return arr1;
  
}

function sym() {
  var args = Array.prototype.slice.call(arguments)
  return args.reduce(function(a,b){
  	return diff(a,b).concat(diff(b,a));
  });
}


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