--- /dev/null
+var unique = require('./unique');
+var filter = require('./filter');
+var contains = require('./contains');
+
+
+ /**
+ * Exclusive OR. Returns items that are present in a single array.
+ * - like ptyhon's `symmetric_difference`
+ */
+ function xor(arr1, arr2) {
+ arr1 = unique(arr1);
+ arr2 = unique(arr2);
+
+ var a1 = filter(arr1, function(item){
+ return !contains(arr2, item);
+ }),
+ a2 = filter(arr2, function(item){
+ return !contains(arr1, item);
+ });
+
+ return a1.concat(a2);
+ }
+
+ module.exports = xor;
+
+