entityManager.js

// request context
function Context(reqArgs, entity) {
  this.req = reqArgs.req;
  this.res = reqArgs.res;
  this.next = reqArgs.next;
  this.entity = entity;
}
Context.prototype.handleErrors = function(fn) {
  var context = this;
  return function(err) {
    if (!err) {
      return context.next(err);
    }
    Array.prototype.shift.apply(arguments);
    return fn.apply(context, arguments);
  };
};
Context.prototype.respond = function(status) {
  var context = this;
  return function(data) {
    return context.res.status(status || 200).send(data);
  };
};
Context.prototype.model = function(modelName) {
  return mongoose.model(modelName || this.entity.modelName);
};

// request handler
function handle(fn) {
  return function() {
    var context = new Context(arguments, this);
    var done = context.handleErrors(context.respond(201));
    return fn.apply(context, done);
  };
}

// entity
function Entity(modelName) {
  this.modelName = this.Model.modelName;
}
Entity.prototype.create = handle(function() {
  var done = this.handleErrors(this.respond(201));
  this.entity.getModel().create(this.req.body, done);
});
Entity.prototype.index = handle(function() {
  var done = this.handleErrors(this.respond(200));
  this.entity.getModel().find({}).sort({createdAt: -1}).exec(done);
});
Entity.prototype.show = handle(function() {
  var id = this.req.param('_id');
  var done = this.handleErrors(this.respond(200));
  this.entity.getModel().findById(id, done);
});
Entity.prototype.update = handle(function() {
  var id = this.req.param('_id');
  var done = this.handleErrors(this.respond(200));
  this.entity.getModel().findByIdAndUpdate(id, this.req.body, done);
});
Entity.prototype.destroy = handle(function() {
  var id = this.req.param('_id');
  var done = this.handleErrors(this.respond(200));
  this.entity.getModel().findByIdAndUpdate(id, {deleted: Date.now()}, done);
});