Problem if the first argument of a callback is not error

[clarkf]

I recently tried using Step with path.exists, which doesn't pass an error argument as the first argument to the callback. Here's the script I tested:

var Step = require('step'),
    path = require('path');
var stuff = ['file1', 'file2', 'file3', 'file4'];
Step(
    function () {
        var group = this.group();
        stuff.forEach(function (item) {
            path.exists(item, group());
        });
    },
    function (err, list) {
        console.log(err);
        console.log(list);
    }
);

This should output null (or some other falsy value) for error, and an array containing false: [false, false, false, false]. Instead, we get:

$ node stepissue.js 
undefined
[ undefined, undefined, undefined, undefined ]

I don't think this is a version compatibility issue, but for good measure, I'm running Step 0.0.4, node 0.4.1 on Ubuntu 10.10.

[creationix]

Step explicitly only supports node style callbacks where it's (err, value). For some reason path.exists is an inconsistency in node that doesn't follow it's own pattern. You can wrap it in a new function that follows the pattern and use that wrapped function.

function pathExists(path, callback) {
  Path.exists(path, function (exists) {
    callback(null, exists);
  });
}

[olecom]

Fix for EventEmitters: #50