# Explanation of code help
**URL:** https://discourse.nodered.org/t/explanation-of-code-help/76319
**Category:** General
**Tags:** function-node
**Created:** [8 March 2023 19:54 UTC](https://discourse.nodered.org/t/explanation-of-code-help/76319 "2023-03-08T19:54:37Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@gerry](https://discourse.nodered.org/u/gerry)
#### Post date: [8 March 2023 19:54 UTC](https://discourse.nodered.org/t/explanation-of-code-help/76319/1 "2023-03-08T19:54:38Z")
@cymplecy posted this code back in January
```auto
if (msg.payload == 1) {
context.set("previousState",!context.get("previousState"))
msg.payload = 1 * context.get("previousState");
return msg;
}
```
I have used this a number of times now and spent the better part of a day googling as to how it worked. I figure if I'm going to use a lot I should understand it. Unfortunately, my google searches all point back to the forum so I am left with no explanation. If someone could please tell me what is happening I would appreciate it.
---
### Author:  [@mickym2](https://discourse.nodered.org/u/mickym2)
#### Post date: [8 March 2023 20:23 UTC](https://discourse.nodered.org/t/explanation-of-code-help/76319/2 "2023-03-08T20:23:30Z")
So what happens is the following, if msg.payload == 1.
in the first line:
```auto
context.set("previousState",!context.get("previousState"))
```
First you get previousState variable from the node context. The content of the is negated by ! - so you have instead of true, false or vice versa. So it acts like a toggle switch. The opposite value is then immediately stored again in the node-context.
The next line:
```auto
msg.payload = 1 * context.get("previousState");
```
As boolean true evaluates to 1 and false to 0 the result is 0 or 1.
To be honest I think the code is in my opinion a little bit laborious.
In my opinion it would be sufficient to use only booleans.
---
### Author:  [@gerry](https://discourse.nodered.org/u/gerry)
#### Post date: [8 March 2023 20:28 UTC](https://discourse.nodered.org/t/explanation-of-code-help/76319/3 "2023-03-08T20:28:11Z")
Thanks for the help
---
### Author:  [@system](https://discourse.nodered.org/u/system)
#### Post date: [22 March 2023 20:28 UTC](https://discourse.nodered.org/t/explanation-of-code-help/76319/4 "2023-03-22T20:28:29Z")
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