Help, I am desperate

Question

I have been making a code. On line 143, it shows an error message, even though it has no indication why. I have tried almost everything to fix it, but still couldn't succeed. Please help :(
https://code.sololearn.com/WZZqmUzplNfz

Answer 1

I use debugger, found that PROJECTILES has 2 array elements, first one is a Projectile object, but the second element is an integer 0, which cause the undefined error.

Answer 2

Use debugger, it would help to pinpoint the problem.

Answer 3

Calviղ I cannot thank you enough. I was suffering for almost 2 hours now

Answer 4

https://content.screencast.com/users/cv2k10/folders/Jing/media/ba728a64-ef13-49a3-894f-a65b5aaa14d5/2019-07-18_2237%20sl%20debugger.png