WooCommerce / Javascript: This code transform the WooCommerce Categories List Widget in an accordion.

custom.js

jQuery(document).ready(function($) {
	$(".widget .product-categories > li > .children li").each(function() {
		if($(this).has(".children")) {
			if(!($(this).hasClass("current-cat-parent"))) {
				$(this).find(".children").first().attr("style", "display:none;")
					.siblings("a").attr("href", "javascript:void(0);");
			}
		}
	});

	$(".widget .product-categories > li > .children li a").click(function() {
		$(this).siblings(".children").first().toggle(300);
	});
});