Update sampleSize.md

snippets/sampleSize.md

@@ -2,8 +2,12 @@
 
 Gets `n` random elements at unique keys from `array` up to the size of `array`.
 
+Shuffle the array using the [Fisher-Yates algorithm](https://github.com/chalarangelo/30-seconds-of-code#shuffle).
+Use `Array.slice()` to get the first `n` elements.
+Omit the second arguent, `n` to get only one element at random from the array.
+
 ```js
-const sampleSize = (arr,n=1) => {
+const sampleSize = ([...arr],n=1) => {
   let m = arr.length;
   while (m) {
     const i = Math.floor(Math.random() * m--);