Example of a Unary operator mutator?

[adjstreams]

Question

I'm trying to create a test project that demonstrates the different types of mutators that StrykerJS will detect, but I can't seem to recreate an example method and test which results in a potential positive Unary operator mutator result.

Stryker environment

+-- @stryker-mutator/core@8.2.6
+-- @stryker-mutator/jest-runner@8.2.6

+-- jest@29.7.0

Additional context