beforeChange (and afterChange) bubble

http://jsfiddle.net/L1c949zf/1/

In the following setup, where each slide of .slider contains its own .sub-slider, currentSlide is logged to the console whenever either slider changes.

$(".slider").slick({
    autoplay: true,
    autoplaySpeed: 4000,
    dots: true
});

$(".sub-slider").slick({
    autoplay: true,
    autoplaySpeed: 1000,
    dots: false,
    arrows: false
});

$(".slider").on('beforeChange', function(event, slick, currentSlide) {
    console.log(currentSlide);
});

The only way I can think, currently, to ensure that it’s the .slider element that has changed is something like

$(".slider").on('beforeChange', function(event, slick, currentSlide) {
    if ($(slick.$slider).hasClass('slider')) {
        console.log(currentSlide);
    }
}

[kenwheeler]

You can also cancel the bubble in a listener on the sub slider

[kenwheeler]

You can check the target to differentiate