onChange keeps doubling up the stroks 
**Describe the bug**
I am trying to develop a whiteboard (multiuser) for my open-source interview pad aka codecollab project 
https://interviewpad.collabmantra.com/001 


**To Reproduce**
Steps to reproduce the behavior:

1. Go to ["interviewpad'](https://interviewpad.collabmantra.com/001)
2. Click on Inspect > Open Console > 
3. On UI click sketch tab and draw few lines u will see 
4. See error

**Expected behavior**
it should not keep doubling it up

https://github.com/darshanmarathe/CodeCollab