Rename js snippets

snippets/js/s/array-union.md

@@ -0,0 +1,20 @@
+---
+title: Array union
+type: snippet
+language: javascript
+tags: [array]
+cover: yellow-white-mug-2
+dateModified: 2020-10-22T20:24:44+03:00
+---
+
+Returns every element that exists in any of the two arrays at least once.
+
+- Create a `Set` with all values of `a` and `b` and convert it to an array.
+
+```js
+const union = (a, b) => Array.from(new Set([...a, ...b]));
+```
+
+```js
+union([1, 2, 3], [4, 3, 2]); // [1, 2, 3, 4]
+```