async.js with bcrypt

genHash.js

var bcrypt = require("bcrypt"),
    async = require("async");

function genHash(username, password, doneCallback) {
    async.waterfall([
        function(hashCallback) {
            bcrypt.genSalt(10, hashCallback);
        },
        function(salt, callback) {
            bcrypt.hash(password, salt, callback);
        }
    ], function(err, hash) {
        doneCallback(err, hash);
    })
}