extend

var Core = {
  ...
  constructor: function() {
    ...
    Methods.constructor.call(this);
    Modules.constructor.call(this);
  }
};

var Methods = {
  ...
};

var Modules = {
  ...
};

module.exports = pd.extend(Core, Methods, Modules, {
  constructor: Core.constructor
});

mixin

var Core = {
  ...
  constructor: function () {
    ...
  }
};

var Methods = {
  ...
};

var Modules = {
  ...
};

module.exports = pd.mixin(Core, Methods, Modules);