I don't understand error reason

Question

I am making a modification fore some game now and there is an error and I don't understand what causes this error. This error happens also in sololearn sandbox

https://code.sololearn.com/W4IMgXz6yUWQ/?ref=app

Answer 1

In line 13 you wrote pt.liquid instead of pt.liquids.

Answer 2

Line 13:
pt.liquid is wrong ;-)

pt.liquids is correct
You just got it wrong the name of object

Correct:
console.log(pt.liquids[c][c2].liquid);

Wrong:
console.log(pt.liquid[c][c2].liquid);

Answer 3

Thanks everyone. I wasn't noticing it 20 minutes