---
id: 5d792535b0b3c198ee3ed6f9
title: Part 43
challengeType: 0
dashedName: part-43
---
# --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])`.
# --hints--
See description above for instructions.
```js
assert(code.replace(/\s/g, '').includes('returnarr.concat([end])'));
```
# --seed--
## --before-user-code--
```html
Spreadsheet
```
## --after-user-code--
```html
```
## --seed-contents--
```html
```
# --solutions--
```html
```