ternary operator

I'm no idea what means ":" and "?" in "return" . How do I google this?

Never thought of using the modulo operator that way! Excellent.

GG bro.. I can imagine the struggle lol

sorry man...trying to get used to the platform

Use spoiler flag next time, please.

How could i be so stupid ? ......

Once I heard that division operation is very "expensive" (programmatically). Isn't better store the division result in a variable to avoid divide twice?

one thing that can be improved: using [...xs] instead of xs.

yeah , that's more clearly than "%1? -1"

Option: define a var for Math.sqrt(sq) to avoid the extra calc. You are calculating Math.sqrt(sq) twice.
The next comment already stated that... woops

an integer returns 0 which is evaluated as false.

The test case is correct though?

[1, 2, 3, 4, 3, 6], not increasing

remove element at index 4

[1, 2, 3, 4, 6], now strictly increasing! Therefore true

what about Test.assertEquals(almostIncreasingSequence([1, 2, 3, 4, 3, 6]), true) ? it will fail testing!