ES6 jQuery plugin definition

jquery.scrollToTop.js

import $ from 'jquery';
import plugin from './plugin';

class ScrollToTop {
    constructor(element, options) {
        const $element = $(element);
        
        $(window).scroll(function () {
            if ($(this).scrollTop() > options.offset) {
                $element.fadeIn();
            } else {
                $element.fadeOut();
            }
        });
        
        $element.click(function (e) {
            e.preventDefault();
            
            $('html, body').animate({
                scrollTop: 0
            }, options.speed);
        });
    }
}

ScrollToTop.DEFAULTS = {
    offset: 100,
    speed: 500,
};

plugin('ScrollToTop', ScrollToTop);

plugin.js

import $ from 'jquery';

/**
 * Generate a jQuery plugin
 * @param pluginName [string] Plugin name
 * @param className [object] Class of the plugin
 * @param shortHand [bool] Generate a shorthand as $.pluginName
 *
 * @example
 * import plugin from 'plugin';
 *
 * class MyPlugin {
 *     constructor(element, options) {
 *         // ...
 *     }
 * }
 *
 * MyPlugin.DEFAULTS = {};
 *
 * plugin('myPlugin', MyPlugin');
 */
export default function plugin(pluginName, className, shortHand = false) {
    let dataName = `__${pluginName}`;
    let old = $.fn[pluginName];

    $.fn[pluginName] = function (option) {
        return this.each(function () {
            let $this = $(this);
            let data = $this.data(dataName);
            let options = $.extend({}, className.DEFAULTS, $this.data(), typeof option === 'object' && option);

            if (!data) {
                $this.data(dataName, (data = new className(this, options)));
            }

            if (typeof option === 'string') {
                data[option]();
            }
        });
    };

    // - Short hand
    if (shortHand) {
        $[pluginName] = (options) => $({})[pluginName](options);
    }

    // - No conflict
    $.fn[pluginName].noConflict = () => $.fn[pluginName] = old;
}