jquery-ui-like bridge for jquery plugins

jquery.bridge.js

/** @const */
var PLUGIN_NAME = 'myPlugin';

$.fn[PLUGIN_NAME] = function(options) {
  var $els = this;

  /* Method call: */
  if (typeof options === 'string') {
    var methodName = options;
    var args = Array.prototype.slice.call(arguments, 1);

    $els.each(function() {
      var instance = $.data(this, 'plugin_' + PLUGIN_NAME);

      if (!instance) {
        throw new Error('Cannot call methods on ' + PLUGIN_NAME + ' prior to initialization; ' +
          'attempted to call method "' + methodName + '".');
      } else if (methodName.charAt(0) === '_' || !$.isFunction(instance[methodName])) {
        throw new Error('No such method "' + methodName + '" for "' +
          PLUGIN_NAME + '" instance.');
      } else {
        instance[methodName].apply(instance, args);
      }
    });
  /* Instantiation: */
  } else {
    $els.each(function() {
      var instance = $.data(this, 'plugin_' + PLUGIN_NAME);
      if (instance) {
        throw new Error('already instantiated "' + PLUGIN_NAME + '" on element.');
      } else {
        $.data(this, 'plugin_' + PLUGIN_NAME, new MyPlugin(this, options));
      }
    });
  }
};