add sampleSize

snippets/sampleSize.md

@@ -0,0 +1,19 @@
+### sampleSize
+
+Gets `n` random elements at unique keys from `array` up to the size of `array`.
+
+```js
+const sampleSize = (arr,n=1) => {
+  let m = arr.length;
+  while (m) {
+    const i = Math.floor(Math.random() * m--);
+    [arr[m], arr[i]] = [arr[i], arr[m]];
+  }
+  return arr.slice(0,n)
+}
+```
+
+```js
+sampleSize([1,2,3],2); // [3,1]
+sampleSize([1,2,3],4); // [2,3,1]
+```