From 6b2840f579322309bdfd7695fae5012e48fb25e1 Mon Sep 17 00:00:00 2001
From: Damien Chazoule <damien.chazoule@gmail.com>
Date: Sun, 3 Oct 2021 15:40:45 +0200
Subject: [PATCH] Added Fisher Yates Algorithm

---
 Sorts/FisherYatesShuffle.js           | 24 ++++++++++++++++++++++++
 Sorts/test/FisherYatesShuffle.test.js | 27 +++++++++++++++++++++++++++
 2 files changed, 51 insertions(+)
 create mode 100644 Sorts/FisherYatesShuffle.js
 create mode 100644 Sorts/test/FisherYatesShuffle.test.js

diff --git a/Sorts/FisherYatesShuffle.js b/Sorts/FisherYatesShuffle.js
new file mode 100644
index 000000000..d15360eef
--- /dev/null
+++ b/Sorts/FisherYatesShuffle.js
@@ -0,0 +1,24 @@
+export const shuffle = (array) => {
+  let maxLength = array.length,
+    temp,
+    idx
+
+  // While there remain elements to shuffle...
+  while (maxLength) {
+    // Pick a remaining element...
+    idx = Math.floor(Math.random() * maxLength--)
+
+    // And swap it with the current element
+    temp = array[maxLength]
+    array[maxLength] = array[idx]
+    array[idx] = temp
+  }
+
+  return array
+}
+
+const array = [0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89]
+console.log('array', array)
+
+const mixedArray = shuffle(array)
+console.log('mixedArray', mixedArray)
diff --git a/Sorts/test/FisherYatesShuffle.test.js b/Sorts/test/FisherYatesShuffle.test.js
new file mode 100644
index 000000000..9bdc7497b
--- /dev/null
+++ b/Sorts/test/FisherYatesShuffle.test.js
@@ -0,0 +1,27 @@
+import { shuffle } from '../fisherYatesShuffle'
+
+describe('shuffle', () => {
+  it('expects to have a new array with same size', () => {
+    const fibonacci = [0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89]
+    const mixedArray = shuffle(fibonacci)
+
+    expect(mixedArray).toHaveLength(fibonacci.length)
+  })
+
+  it('expects to have a new array with same values', () => {
+    const fibonacci = [0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89]
+    const mixedArray = shuffle(fibonacci)
+
+    expect(mixedArray).toContain(0)
+    expect(mixedArray).toContain(1)
+    expect(mixedArray).toContain(2)
+    expect(mixedArray).toContain(3)
+    expect(mixedArray).toContain(5)
+    expect(mixedArray).toContain(8)
+    expect(mixedArray).toContain(13)
+    expect(mixedArray).toContain(21)
+    expect(mixedArray).toContain(34)
+    expect(mixedArray).toContain(55)
+    expect(mixedArray).toContain(89)
+  })
+})