jQuery UI widgetみたいにAPIを公開して拡張する

argumentsとか書いてるけど、ひとつしかないとき

function MyMethod(conf, arguments) {
  // return new MyMethod
}
// ...
MyMethod.prototype._callAPI = function(api, arguments) {
  var self = this;
  if ( typeof self[api] !== 'function' ) {
    throw api + ' does not exist of MyMethod methods.';
  } else
  if ( /^_/.test(api) && typeof self[api] === 'function' ) {
    throw 'Method begins with an underscore are not exposed.';
  }
  return self[api](arguments);
};
MyMethod.prototype._privateMethod = function() {
  // do something
};
MyMethod.prototype.publicMethod = function() {
  // do something
};

// $.fn extend
jQuery.fn.myMethod = function(conf, arguments) {
  var my_method = this.data('myMethod');

  if ( my_method ) {
    return my_method._callAPI(conf, arguments);
  } else {
    my_method = MyMethod(this, conf);
    this.data('myMethod', my_method);
    return this;
  }
};

用意しとけば

var $my_method = $(hoge).myMethod({ ... });

// You cannot call private methods
$my_method.myMethod('_privateMethod');
=> Error thrown: Uncaught Method begins with an underscore are not exposed.

$my_method.myMethod('publicMethod');
=> OK