Easy to Read One-Liner Solution
\nlet getConcatenation = function (nums) {\n    return [...nums, ...nums]\n}\n\nFound this solution helpful? \nConsider showing support by upvoting this post. \
```\nlet getConcatenation = function (nums) {\n    return [...nums, ...nums]\n}\n```\n*Found this solution helpful? \nConsider showing support by upvoting this post. \nThank you and happy hacking!*\n
['JavaScript']