# Can a \`change\` node access a globaI variable if it's an array?
**URL:** https://discourse.nodered.org/t/can-a-change-node-access-a-globai-variable-if-its-an-array/23629
**Category:** General
**Created:** [25 March 2020 16:15 UTC](https://discourse.nodered.org/t/can-a-change-node-access-a-globai-variable-if-its-an-array/23629 "2020-03-25T16:15:46Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@zenofmud](https://discourse.nodered.org/u/zenofmud)
#### Post date: [25 March 2020 16:15 UTC](https://discourse.nodered.org/t/can-a-change-node-access-a-globai-variable-if-its-an-array/23629/1 "2020-03-25T16:15:46Z")
I'm trying to build a remote tic-tac-toe game with my grandson. I'm storing the 'board' in a global array 'board' as a 3x3 array
```auto
var b = [[9,9,9],[9,9,9],[9,9,9]]
global.set("board",b)
```
The board is a set of buttons and each button sends a payload like this for r0,c0 `{"r":0,"c":0}`
What I want to do in a `change` node is set global.board[0][0] to a number but if I use
`global.board[msg.payload.r][msg.payload.c]` I get an error.
Is there a way to achieve this?
---
### Author:  [@JGKK](https://discourse.nodered.org/u/JGKK)
#### Post date: [25 March 2020 16:37 UTC](https://discourse.nodered.org/t/can-a-change-node-access-a-globai-variable-if-its-an-array/23629/2 "2020-03-25T16:37:34Z")
If i use global.board[0][0] it works, using a message property like global.board[msg.array.x][msg.array.y] doesnt work for me either. Maybe use a function node in this case. It will work there probably.
---
### Author:  [@zenofmud](https://discourse.nodered.org/u/zenofmud)
#### Post date: [25 March 2020 16:48 UTC](https://discourse.nodered.org/t/can-a-change-node-access-a-globai-variable-if-its-an-array/23629/3 "2020-03-25T16:48:03Z")
Yup I've already swapped to using a function but I'd still like to know if it is doable.
This is what I did in the function node
```auto
var r = msg.payload.r
var c = msg.payload.c
var b = global.get("board")
b[r][c] = 2
global.set("board",b)
return msg
```
---
### Author:  [@zenofmud](https://discourse.nodered.org/u/zenofmud)
#### Post date: [24 May 2020 16:48 UTC](https://discourse.nodered.org/t/can-a-change-node-access-a-globai-variable-if-its-an-array/23629/4 "2020-05-24T16:48:04Z")
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