Flow control for object building - passes object as first param.

waterflow.js

function flow(target, items, cb){
  forEach(items, function(item, next){
    if (Array.isArray(item)){
      item[0].apply(this, [target].concat(item.slice(1), cb))
    } else {
      item(target, next)
    }
  }, function(err){
    if (err) return cb&&cb(err)
    cb(null, target)
  })
}