Calling next step with parameters in Node.js Step module

I've just started using Step, and I'm trying to get the 开发者_StackOverflow中文版stat information of all files in a directory.

However as I'm calling fs.stat in the second step, I still need the full path. How can I pass it to the next method? I've tried this(directory) but it didn't work as I expected.

var getFiles = step.fn(
    function readDir(directory) {
        var p = path.join(__dirname, directory);
        fs.readdir(p, this); // *** How do I pass 'directory' to the next method?
    },

    function readFiles(err, results, directory) {
        if (err) throw err;
        // Create a new group
        var group = this.group();
        results.forEach(function (filename) {
            console.log(filename);
            var p = path.join(__dirname, directory, filename);
            // fs.stat requires a full path
            fs.stat(p, group()); // Could be this.parallel() ??
        });
    }
);

// later...
var files = getFiles('data');

As I understand it, readDir gets called once, then readFiles gets called, but all in series as fs.readdir's callback just gets called once, with an array of files.

You could use a variable scoped outside getFiles (hacky), or you could also use a closure.

Personally, I would switch from step to async (https://github.com/caolan/async). The waterfall method provided in async is what you're really looking for. Async has the same functionality as step and more.

fs.readdir(p, (function(err, files) {
  this(err, files, directory);
}).bind(this)); 

this is just a function. You can call it explicitly.

You could always use Q-Oper8:

https://github.com/robtweed/Q-Oper8

Then you could safely use the sync fs methods which might make it easier to do what you're wanting to do.