# Change javascript code in function node

**URL:** https://discourse.nodered.org/t/change-javascript-code-in-function-node/15891
**Category:** General
**Created:** [25 September 2019 14:24 UTC](https://discourse.nodered.org/t/change-javascript-code-in-function-node/15891 "2019-09-25T14:24:08Z")
**Posts on this page:** 1
**Showing post:** 10

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### Author: ![chandra123](https://avatars.discourse-cdn.com/v4/letter/c/958977/32.png) [@chandra123](https://discourse.nodered.org/u/chandra123)
#### Post date: [26 September 2019 09:25 UTC](https://discourse.nodered.org/t/change-javascript-code-in-function-node/15891/10 "2019-09-26T09:25:20Z")

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@bakman2  
Hi,  
I have written one rule as  
sensorData=JSON.parse(msg.payload);  
var a=sensordata.dp1;  
var a=sensordata.dp2;  
var c=a+b;  
msg.payload=c;  
return msg;

this is addition rule of 2 datapoints  
Now I want to change it to multiplication rule by external rest-api or anything possible.  
how can I do that?

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