How to extend Bootstrap JavaScript Plugin? See below :)

kepek.modal.js

+function ($) {
  'use strict';

  // BOOTSTRAP
  
  var Bootstrap = $.fn.modal.Constructor;

  // MODAL CLASS DEFINITION
  // ======================

  var Modal = function (element, options) {
    this.options   = options
    this.$element  = $(element)
    this.$backdrop =
    this.isShown   = null

    if (this.options.remote) {
      this.$element
        .find('.modal-content')
        .load(this.options.remote, $.proxy(function () {
          this.$element.trigger('loaded.bs.modal')
        }, this))
    }

  };

  Modal.DEFAULTS = {
    backdrop: true,
    keyboard: true,
    show: true
  }

  Modal.prototype = $.extend(true, Bootstrap.prototype, {});

  Modal.prototype.toggle = function (_relatedTarget) {

    /**
     * Method body here.
     */
    
    console.log('Method body here.')

    return this[!this.isShown ? 'show' : 'hide'](_relatedTarget)
  }


  // REMOVE OLD PLUGIN
  // =======================
  
  delete $.fn.modal;


  // MODAL PLUGIN DEFINITION
  // =======================

  var old = $.fn.modal;

  $.fn.modal = function (option, _relatedTarget) {
    return this.each(function () {
      var $this   = $(this)
      var data    = $this.data('bs.modal')
      var options = $.extend({}, Modal.DEFAULTS, $this.data(), typeof option == 'object' && option)

      if (!data) $this.data('bs.modal', (data = new Modal(this, options)))
      if (typeof option == 'string') data[option](_relatedTarget)
      else if (options.show) data.show(_relatedTarget)
    })
  }

  $.fn.modal.Constructor = Modal;


  // MODAL NO CONFLICT
  // =================

  $.fn.modal.noConflict = function () {
    $.fn.modal = old
    return this
  }
  

}(jQuery);