如何在Swiper中检查方向转换

Question

我正在用Swiper编码滑块，但是在向左/向右滑动时检查方向转换时遇到问题。我需要检查进度功能中的方向，在代码中的正确位置进行注释。

var headerSlider = new Swiper('.swiper-header', {
    grabCursor: true,
    watchSlidesProgress: true,
    slidesPerView: 1,
    on: {
        progress: function() {
            for (var i = 0; i < this.slides.length; i++) {
                var slideProgress = this.slides[i].progress;
                var innerOffset = this.width * 0.5;
                var innerTranslate = slideProgress * innerOffset;
                //
                //I need here to check direction transition.
                //Like slide to prev or next slide
                //
                this.slides[i].querySelector(".slide-image").style.transform = "translate3d(" + innerTranslate + "px, 0, 0)";
            }
        },

        touchStart: function() {
            for (var i = 0; i < this.slides.length; i++) {
                this.slides[i].style.transition = "";
            }
            );
        },

        setTransition: function(speed) {
            for (var i = 0; i < this.slides.length; i++) {
                this.slides[i].style.transition = speed + "ms";
                this.slides[i].querySelector(".slide-image").style.transition =
                    speed + "ms";
            }
        }
    }});