From 02327955926573f7d75cf13be9f5bb35bcff58c2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E6=B5=AA=E6=B5=AA=E6=B5=AA?= <675483520@qq.com>
Date: Fri, 10 Aug 2018 15:47:20 +0800
Subject: [PATCH 1/3] Update symmetricDifference

No const
One time new Set()
One line code style
---
 snippets/symmetricDifference.md | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/snippets/symmetricDifference.md b/snippets/symmetricDifference.md
index 6f13806e4..1f76f8f25 100644
--- a/snippets/symmetricDifference.md
+++ b/snippets/symmetricDifference.md
@@ -5,11 +5,9 @@ Returns the symmetric difference between two arrays.
 Create a `Set` from each array, then use `Array.filter()` on each of them to only keep values not contained in the other.
 
 ```js
-const symmetricDifference = (a, b) => {
-  const sA = new Set(a),
-    sB = new Set(b);
-  return [...a.filter(x => !sB.has(x)), ...b.filter(x => !sA.has(x))];
-};
+const symmetricDifference = (a, b) => [
+  ...new Set([...a.filter(v => !b.includes(v)), ...b.filter(v => !a.includes(v))])
+];
 ```
 
 ```js

From 4de6aceb044a0f38961f2709cf29be17e79c4c27 Mon Sep 17 00:00:00 2001
From: Angelos Chalaris <chalarangelo@gmail.com>
Date: Fri, 17 Aug 2018 08:37:08 +0300
Subject: [PATCH 2/3] Added uniqueSymmetricDifference and updated
 symmetricDifference

---
 snippets/symmetricDifference.md                  | 11 +++++++----
 snippets/uniqueSymmetricDifference.md            | 16 ++++++++++++++++
 tag_database                                     |  1 +
 .../uniqueSymmetricDifference.js                 |  4 ++++
 .../uniqueSymmetricDifference.test.js            | 12 ++++++++++++
 5 files changed, 40 insertions(+), 4 deletions(-)
 create mode 100644 snippets/uniqueSymmetricDifference.md
 create mode 100644 test/uniqueSymmetricDifference/uniqueSymmetricDifference.js
 create mode 100644 test/uniqueSymmetricDifference/uniqueSymmetricDifference.test.js

diff --git a/snippets/symmetricDifference.md b/snippets/symmetricDifference.md
index 1f76f8f25..2414218bd 100644
--- a/snippets/symmetricDifference.md
+++ b/snippets/symmetricDifference.md
@@ -5,11 +5,14 @@ Returns the symmetric difference between two arrays.
 Create a `Set` from each array, then use `Array.filter()` on each of them to only keep values not contained in the other.
 
 ```js
-const symmetricDifference = (a, b) => [
-  ...new Set([...a.filter(v => !b.includes(v)), ...b.filter(v => !a.includes(v))])
-];
+const symmetricDifference = (a, b) => {
+  const sA = new Set(a),
+    sB = new Set(b);
+  return [...a.filter(x => !sB.has(x)), ...b.filter(x => !sA.has(x))];
+};
 ```
 
 ```js
-symmetricDifference([1, 2, 3], [1, 2, 4]); // [3,4]
+symmetricDifference([1, 2, 3], [1, 2, 4]); // [3, 4]
+symmetricDifference([1, 2, 2], [1, 3, 1]); // [2, 2, 3]
 ```
diff --git a/snippets/uniqueSymmetricDifference.md b/snippets/uniqueSymmetricDifference.md
new file mode 100644
index 000000000..8d2f22468
--- /dev/null
+++ b/snippets/uniqueSymmetricDifference.md
@@ -0,0 +1,16 @@
+### uniqueSymmetricDifference
+
+Returns the unique symmetric difference between two arrays.
+
+Use `Array.filter()` and `Array.includes()` on each array to remove values contained in the other, then create a `Set` from the results, removing duplicate values.
+
+```js
+const uniqueSymmetricDifference = (a, b) => [
+  ...new Set([...a.filter(v => !b.includes(v)), ...b.filter(v => !a.includes(v))])
+];
+```
+
+```js
+uniqueSymmetricDifference([1, 2, 3], [1, 2, 4]); // [3, 4]
+uniqueSymmetricDifference([1, 2, 2], [1, 3, 1]); // [2, 3]
+```
diff --git a/tag_database b/tag_database
index 92f0c81ad..25701b373 100644
--- a/tag_database
+++ b/tag_database
@@ -302,6 +302,7 @@ unionWith:array,function
 uniqueElements:array
 uniqueElementsBy:array,function
 uniqueElementsByRight:array,function
+uniqueSymmetricDifference:array,math
 untildify:node,string
 unzip:array
 unzipWith:array,function,advanced
diff --git a/test/uniqueSymmetricDifference/uniqueSymmetricDifference.js b/test/uniqueSymmetricDifference/uniqueSymmetricDifference.js
new file mode 100644
index 000000000..62cb18a5f
--- /dev/null
+++ b/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;
diff --git a/test/uniqueSymmetricDifference/uniqueSymmetricDifference.test.js b/test/uniqueSymmetricDifference/uniqueSymmetricDifference.test.js
new file mode 100644
index 000000000..788d1f65e
--- /dev/null
+++ b/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]);
+});

From 609f80850ff94b034650a8bb476325129308c957 Mon Sep 17 00:00:00 2001
From: Angelos Chalaris <chalarangelo@gmail.com>
Date: Fri, 17 Aug 2018 08:39:04 +0300
Subject: [PATCH 3/3] Improved descriptions

---
 snippets/symmetricDifference.md                      | 2 +-
 snippets/uniqueSymmetricDifference.md                | 2 +-
 test/symmetricDifference/symmetricDifference.test.js | 3 +++
 3 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/snippets/symmetricDifference.md b/snippets/symmetricDifference.md
index 2414218bd..854af0f30 100644
--- a/snippets/symmetricDifference.md
+++ b/snippets/symmetricDifference.md
@@ -1,6 +1,6 @@
 ### symmetricDifference
 
-Returns the symmetric difference between two arrays.
+Returns the symmetric difference between two arrays, without filtering out duplicate values.
 
 Create a `Set` from each array, then use `Array.filter()` on each of them to only keep values not contained in the other.
 
diff --git a/snippets/uniqueSymmetricDifference.md b/snippets/uniqueSymmetricDifference.md
index 8d2f22468..99afdadfe 100644
--- a/snippets/uniqueSymmetricDifference.md
+++ b/snippets/uniqueSymmetricDifference.md
@@ -1,6 +1,6 @@
 ### uniqueSymmetricDifference
 
-Returns the unique symmetric difference between two arrays.
+Returns the unique symmetric difference between two arrays, not containing duplicate values from either array.
 
 Use `Array.filter()` and `Array.includes()` on each array to remove values contained in the other, then create a `Set` from the results, removing duplicate values.
 
diff --git a/test/symmetricDifference/symmetricDifference.test.js b/test/symmetricDifference/symmetricDifference.test.js
index 7fc364488..c96e3b5a6 100644
--- a/test/symmetricDifference/symmetricDifference.test.js
+++ b/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]);
+});