Merge pull request #709 from EthanOrange/patch-3

Update symmetricDifference, add uniqueSymmetricDifference

test/symmetricDifference/symmetricDifference.test.js

@@ -7,3 +7,6 @@ test('symmetricDifference is a Function', () => {
 test('Returns the symmetric difference between two arrays.', () => {
   expect(symmetricDifference([1, 2, 3], [1, 2, 4])).toEqual([3, 4]);
 });
+test('Returns duplicates from one array', () => {
+  expect(symmetricDifference([1, 2, 2], [1, 3, 1])).toEqual([2, 2, 3]);
+});

test/uniqueSymmetricDifference/uniqueSymmetricDifference.js

@@ -0,0 +1,4 @@
+const uniqueSymmetricDifference = (a, b) => [
+  ...new Set([...a.filter(v => !b.includes(v)), ...b.filter(v => !a.includes(v))])
+];
+module.exports = uniqueSymmetricDifference;

test/uniqueSymmetricDifference/uniqueSymmetricDifference.test.js

@@ -0,0 +1,12 @@
+const expect = require('expect');
+const uniqueSymmetricDifference = require('./uniqueSymmetricDifference.js');
+
+test('uniqueSymmetricDifference is a Function', () => {
+  expect(uniqueSymmetricDifference).toBeInstanceOf(Function);
+});
+test('Returns the symmetric difference between two arrays.', () => {
+  expect(uniqueSymmetricDifference([1, 2, 3], [1, 2, 4])).toEqual([3, 4]);
+});
+test('Does not return duplicates from one array', () => {
+  expect(uniqueSymmetricDifference([1, 2, 2], [1, 3, 1])).toEqual([2, 3]);
+});