Make rxjs dependency optional

I'm finally going to pick up this pattern for making reducers, but my project does not use rxjs at all.

Is there any way to make the dependency of rxjs optional? Or would it be a better idea to fork this code?

It looks like optional dependencies may be supported by npm, but I have never used them before.

Do you worry about bundle size? I belive core rxjs 6 code should be pretty small.