Allow to pass a fs module

[mszczepanczyk]

No description provided.

[emschwartz]

Is this for testing or production? Could you use something like mock-require instead?

[toolness]

Oh I think this is for production, so that a custom fs module can be passed in if the user is running on a JS unikernel or something? Or maybe I'm confusing this with a different PR...

[mszczepanczyk]

@emschwartz @toolness yup I'm thinking about using this in production. It's viable to monkey patch the node fs module and replace it with a custom one but it's not very elegant and kinda dodgy.

If there's a will to merge this pr I'll rebase it against newest changes and fix tests.

[toolness]

Cool, I'm fine with merging it, though can you also document it in the README and explain a bit abut how/why one would use it?

[mszczepanczyk]

@toolness ok sure