There are problems with your readFile and writeFile functions.  These functions are asynchronous.  As such, the callbacks you pass to `fs.writeFile()` and to `fs.readFile()` are called some time in the future, long after `fs.readFile()` and `fs.writeFile()` have already returned and finished executing.

As such, the return value you have in those callbacks just returns back into the bowels of the file I/O sub-system and does not go back to any of your code.

So, as you have the code written, you have these problems:

1. There's no way for the code that calls `readFile()` or `writefile()` to know when either function has completed.

2. There's no way for the code that calls `writeFile()` to know when that function succeeded or failed.

3. There's no way for the code that calls `readFile()` to know if an error occured.

Your functions will need to accept either a completion callback or they will need to return a promise because that's how the caller gets completion and error information.

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Then, once you've fixed the above issues, you'll find that you've hardly changed `fs.readFile()` and `fs.writeFile()` much at all.  Pretty much all you will have done is default the encoding to `utf8` since everythning will be pretty much the same.  I'd have to say that this module doesn't really seem worth it.