Incremental file saved incrementally during execution rather than whole thing at the end

[palunjm]

Is your feature request related to a problem? Please describe.
If a mutation testing run is interrupted prematurely the results up to that point are lost.

Describe the solution you'd like
It would be nice to have an option to update the incremental file after X number of mutations (maybe not after every mutation passes/fails). That way you could still make progress towards completing a large increment even if you need to interrupt the process.

Describe alternatives you've considered
I have attempted to write a node function which will mutate a file at a time but I am having trouble getting it to correctly update the files at the end of each run for some reason. Also, there is the overhead of startup for each file.

[nicojs]

Hmm, this is a great feature 👏.

As an alternative, we could also register an unexpected exit handler. So when you exit (for example, by pressing CTRL+C) we could write the intermediate file to disk.

Do you want to work on this feature?