Defining the plugin methods

Now that we have our plugin well declared, we must fill the logic for it. We will create methods inside the prototype to create this behavior. We will only show this portion of the plugin code here.

The first method that we will create is init(). We will call it later to start the plugin. Before that, we have a few steps:

• Initial verifications

• Assigning the plugin elements and prerequisites

• Loading the original Bootstrap template

• Starting the Bootstrap plugin

The initialize method and plugin verifications

Actually, we have only one requirement from the Bootstrap original carousel plugin: the outmost div must have an id. Let's create the init function while making this assertion:

BootstrapCarousel.prototype = {
  init: function () {
    if(!this.$element.attr('id')){
      throw 'You must provide an id for the Bootstrap Carousel element.';
    }

    this.$element.addClass('slide carousel');
  }
};

Therefore, we check if the element has the attribute id using this.$element...