Slider

(function($){
    $.fn.mySlider = function(options) {

        let settings = $.extend({
            'speed': 2000,
            'itemSelector': '.slider__item',
            'dotSelector': '.slider__dot',
            'itemActiveClass': 'slider__item_active',
            'dotActiveClass': 'slider__dot_active',
            'nextBtnSelector': '.slider__arrow-right',
            'prevBtnSelector': '.slider__arrow-left'
        }, options);

        return this.each(function() {
            let items = $(this).find(settings.itemSelector);
            let dots = $(this).find(settings.dotSelector);
            let cntSlides = items.length;
            let nowSlide = -1;

            function hidden(nowSlide){
                items.eq(nowSlide).removeClass(settings.itemActiveClass);
                dots.eq(nowSlide).removeClass(settings.dotActiveClass);
            }

            function show(nowSlide){
                items.eq(nowSlide).addClass(settings.itemActiveClass);
                dots.eq(nowSlide).addClass(settings.dotActiveClass);
            }

            function goTo(newSlide){
                hidden(nowSlide);
                nowSlide = newSlide;
                show(nowSlide);
            }

            function next(){
                goTo(nowSlide + 1  < cntSlides ? nowSlide + 1 : 0);
            }

            function prev(){
                goTo(nowSlide - 1 < 0 ? cntSlides - 1 : nowSlide - 1);
            }

            show(0);
            let sliderIntervalId = setInterval(next, settings.speed);

            dots.click(function(){
                clearInterval(sliderIntervalId);
                goTo($(this).index());
            })

            $(this).find(settings.nextBtnSelector).click(() => {
                clearInterval(sliderIntervalId);
                next();
            });

            $(this).find(settings.prevBtnSelector).click(() => {
                clearInterval(sliderIntervalId);
                prev();
            });
        });

    };
})(jQuery);