From 8ab363156329f40f755e4f10382a2e692a89ed3f Mon Sep 17 00:00:00 2001
From: SukkaW <isukkaw@gmail.com>
Date: Fri, 21 Aug 2020 17:34:56 +0800
Subject: [PATCH] feat: Array.shuffle

---
 _es5-ext/array/shuffle.js | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)
 create mode 100644 _es5-ext/array/shuffle.js

diff --git a/_es5-ext/array/shuffle.js b/_es5-ext/array/shuffle.js
new file mode 100644
index 00000000..37c54b4d
--- /dev/null
+++ b/_es5-ext/array/shuffle.js
@@ -0,0 +1,25 @@
+"use strict";
+
+var random = Math.random, isArray = Array.isArray;
+
+module.exports = function (input) {
+	if (!isArray(input)) throw new TypeError("input must be an Array!");
+
+	// Make a clone of original array
+	var $array = input.slice(0);
+
+	var sourceIndex = input.length;
+	var destinationIndex = 0;
+
+	// Pre-assign the size of array
+	var shuffled = new Array(sourceIndex);
+
+	while (sourceIndex) {
+		// eslint-disable-next-line no-bitwise
+		var randomIndex = (sourceIndex * random()) | 0;
+		shuffled[destinationIndex++] = $array[randomIndex];
+		$array[randomIndex] = $array[--sourceIndex];
+	}
+
+	return shuffled;
+};