index.js

var zsf = require('@zombiec0rn/zombie-service-format')
var hash = require('object-hash')

var unify = function(config) { 
  return (config instanceof Array) ? config : [config]
}
var uid = function(container) { 
  return container.fingerprint || hash(container)
}

module.exports = function(current, wanted) {
  var _current = zsf.validate(unify(current)).map(uid)
  var _wanted  = zsf.validate(unify(wanted)).map(uid)

  var keep   = wanted.filter(function(container)  { return _current.indexOf(uid(container)) >= 0 }) // keep   - in wanted & current
  var _keep  = keep.map(uid)
  var add    = wanted.filter(function(container)  { return _keep.indexOf(uid(container)) < 0 })     // add    - in wanted & not in keep
  var remove = current.filter(function(container) { return _keep.indexOf(uid(container)) < 0 })     // remove - in current & not in keep

  return {
    add : add,
    keep : keep,
    remove : remove
  }
}

module.exports.fingerprint = hash