// chai-change plugin doesn't seem to work anymore (chaijs/chai-change#4)

Seems like assertChanges in assertions.js expects object, prop. It limits the usage of this kind of assertion, as I can't do:

assert.increases(
  someOperation,
  () => getSomething().length
)

It's good in cases I use immutable data, and getSomething returns different object completely.

RSpec's change matcher has this feature, it can get either an object and a method name or a function for more arbitrary operations.

https://www.relishapp.com/rspec/rspec-expectations/docs/built-in-matchers/change-matcher