--- id: 5d792535b0b3c198ee3ed6f9 title: Part 043 challengeType: 0 isBeta: true --- ## Description
The `concat` method can also accept arrays: ```js [1,2,3].concat([4, 5]); // [1, 2, 3, 4, 5] [1,2,3].concat([4, 5], [6, 7]); // [1, 2, 3, 4, 5, 6, 7] ``` Use this form of `concat` by passing an array with just `end` to it: `arr.concat([end])`.
## Instructions
## Tests
```yml tests: - text: See description above for instructions. testString: assert(code.replace(/\s/g, "").includes("returnarr.concat([end])")); ```
## Challenge Seed
```html ```
### Before Test
```html Spreadsheet
```
### After Test
```html ```
## Solution
```html ```