Node.js create folder or use existing

I already have read the documentation of Node.js and, unless if I missed something, it does not tell what the parameters contain in certain operations, in particular fs.mkdir(). As you can see in the documentation, it’s not very much.

Currently, I have this code, which tries to create a folder or use an existing one instead:

fs.mkdir(path,function(e){
    if(!e || (e && e.code === 'EEXIST')){
        //do something with contents
    } else {
        //debug
        console.log(e);
    }
});

But I wonder is this the right way to do it? Is checking for the code EEXIST the right way to know that the folder already exists? I know I can do fs.stat() before making the directory, but that would already be two hits to the filesystem.

Secondly, is there a complete or at least a more detailed documentation of Node.js that contains details as to what error objects contain, what parameters signify etc.