diff --git a/src/core/jquery-ext.js b/src/core/jquery-ext.js
index b7a46a211..367aeab35 100644
--- a/src/core/jquery-ext.js
+++ b/src/core/jquery-ext.js
@@ -12,7 +12,8 @@ var methods = {
         var settings = {
             time: 3 /* time it will wait before moving to "timeout" after a move event */,
             initialTime: 8 /* time it will wait before first adding the "timeout" class */,
-            exceptionAreas: [] /* IDs of elements that, if the mouse is over them, will reset the timer */,
+            exceptionAreas:
+                [] /* IDs of elements that, if the mouse is over them, will reset the timer */,
         };
         return this.each(function () {
             var $this = $(this),
@@ -156,43 +157,6 @@ $.extend($.expr[":"], {
     },
 });
 
-// Make Visible in scroll
-$.fn.makeVisibleInScroll = function (parent_id) {
-    var absoluteParent = null;
-    if (typeof parent_id === "string") {
-        absoluteParent = $("#" + parent_id);
-    } else if (parent_id) {
-        absoluteParent = $(parent_id);
-    }
-
-    return this.each(function () {
-        var $this = $(this),
-            parent;
-        if (!absoluteParent) {
-            parent = $this.parents(":scrollable");
-            if (parent.length > 0) {
-                parent = $(parent[0]);
-            } else {
-                parent = $(window);
-            }
-        } else {
-            parent = absoluteParent;
-        }
-
-        var elemTop = $this.position().top;
-        var elemBottom = $this.height() + elemTop;
-
-        var viewTop = parent.scrollTop();
-        var viewBottom = parent.height() + viewTop;
-
-        if (elemTop < viewTop) {
-            parent.scrollTop(elemTop);
-        } else if (elemBottom > viewBottom - parent.height() / 2) {
-            parent.scrollTop(elemTop - (parent.height() - $this.height()) / 2);
-        }
-    });
-};
-
 //Work around warning for jQuery 3.x:
 //JQMIGRATE: jQuery.fn.offset() requires an element connected to a document
 $.fn.safeOffset = function () {
@@ -212,67 +176,6 @@ $.fn.safeOffset = function () {
     return $.fn.offset.apply(this, arguments);
 };
 
-//Make absolute location
-$.fn.setPositionAbsolute = function (element, offsettop, offsetleft) {
-    return this.each(function () {
-        // set absolute location for based on the element passed
-        // dynamically since every browser has different settings
-        var $this = $(this);
-        var thiswidth = $(this).width();
-        var pos = element.safeOffset();
-        var width = element.width();
-        var height = element.height();
-        var setleft = pos.left + width - thiswidth + offsetleft;
-        var settop = pos.top + height + offsettop;
-        $this.css({
-            "z-index": 1,
-            "position": "absolute",
-            "marginLeft": 0,
-            "marginTop": 0,
-            "left": setleft + "px",
-            "top": settop + "px",
-            "width": thiswidth,
-        });
-        $this.remove().appendTo("body").show();
-    });
-};
-
-$.fn.positionAncestor = function (selector) {
-    var left = 0;
-    var top = 0;
-    this.each(function () {
-        // check if current element has an ancestor matching a selector
-        // and that ancestor is positioned
-        var $ancestor = $(this).closest(selector);
-        if ($ancestor.length && $ancestor.css("position") !== "static") {
-            var $child = $(this);
-            var childMarginEdgeLeft =
-                $child.safeOffset().left - parseInt($child.css("marginLeft"), 10);
-            var childMarginEdgeTop =
-                $child.safeOffset().top - parseInt($child.css("marginTop"), 10);
-            var ancestorPaddingEdgeLeft =
-                $ancestor.safeOffset().left +
-                parseInt($ancestor.css("borderLeftWidth"), 10);
-            var ancestorPaddingEdgeTop =
-                $ancestor.safeOffset().top +
-                parseInt($ancestor.css("borderTopWidth"), 10);
-            left = childMarginEdgeLeft - ancestorPaddingEdgeLeft;
-            top = childMarginEdgeTop - ancestorPaddingEdgeTop;
-            // we have found the ancestor and computed the position
-            // stop iterating
-            return false;
-        }
-    });
-    return {
-        left: left,
-        top: top,
-    };
-};
-
-$.fn.findInclusive = function (selector) {
-    return this.find("*").addBack().filter(selector);
-};
-
 $.fn.slideIn = function (speed, easing, callback) {
     return this.animate({ width: "show" }, speed, easing, callback);
 };
@@ -281,20 +184,4 @@ $.fn.slideOut = function (speed, easing, callback) {
     return this.animate({ width: "hide" }, speed, easing, callback);
 };
 
-// case-insensitive :contains
-$.expr[":"].Contains = function (a, i, m) {
-    return $(a).text().toUpperCase().indexOf(m[3].toUpperCase()) >= 0;
-};
-
-$.fn.scopedFind = function (selector) {
-    /*  If the selector starts with an object id do a global search,
-     *  otherwise do a local search.
-     */
-    if (selector.indexOf("#") === 0) {
-        return $(selector);
-    } else {
-        return this.find(selector);
-    }
-};
-
 export default undefined;
diff --git a/src/core/jquery-ext.test.js b/src/core/jquery-ext.test.js
deleted file mode 100644
index 73e298d07..000000000
--- a/src/core/jquery-ext.test.js
+++ /dev/null
@@ -1,17 +0,0 @@
-import "./jquery-ext";
-import $ from "jquery";
-
-describe("Find including top-level elements", function () {
-    it("Top-level elements are included", function () {
-        var $col = $(
-                "<div>" +
-                    "<p></p>" +
-                    "<span></span>" +
-                    "</div>" +
-                    "<div></div>" +
-                    "<p></p>"
-            ),
-            $match = $col.findInclusive("div p");
-        expect($match.length).toBe(1);
-    });
-});
diff --git a/src/core/registry.js b/src/core/registry.js
index 4418ca93a..c666adfee 100644
--- a/src/core/registry.js
+++ b/src/core/registry.js
@@ -20,6 +20,7 @@ import $ from "jquery";
 import dom from "./dom";
 import logging from "./logging";
 import utils from "./utils";
+import "./remove";
 
 const log = logging.getLogger("registry");
 const disable_re = /patterns-disable=([^&]+)/g;
diff --git a/src/core/url.js b/src/core/url.js
deleted file mode 100644
index 601231d4f..000000000
--- a/src/core/url.js
+++ /dev/null
@@ -1,63 +0,0 @@
-/**
- * Patterns URL - URL parsing utilities
- *
- * Copyright 2013 Simplon B.V.
- */
-
-function UrlArgumentParser() {
-    this._cache = null;
-    if (window.addEventListener) window.addEventListener("popstate", this._reset);
-}
-
-UrlArgumentParser.prototype = {
-    space_pattern: /\+/g,
-    keyvalue_pattern: /^(.+?)(?:=(.*))/,
-
-    _reset: function UrlArgumentParser_reset() {
-        this._cache = null;
-    },
-
-    _decodeQS: function UrlArgumentParser_decodeQS(bit) {
-        return decodeURIComponent(bit.replace(this.space_pattern, " "));
-    },
-
-    _parse: function UrlArgumentParser_parse(qs) {
-        var query = /\?(.+)/.exec(qs),
-            params = {};
-
-        if (query === null) return params;
-
-        var parameters = query[1].split("&"),
-            i,
-            parts,
-            key,
-            value;
-
-        for (i = 0; i < parameters.length; i++) {
-            if ((parts = this.keyvalue_pattern.exec(parameters[i])) === null) {
-                key = this._decodeQS(parameters[i]);
-                value = null;
-            } else {
-                key = this._decodeQS(parts[1]);
-                value = this._decodeQS(parts[2]);
-            }
-
-            if (params[key] === undefined) params[key] = [];
-            params[key].push(value);
-        }
-
-        return params;
-    },
-
-    get: function UrlArgumentParser_get() {
-        if (this._cache === null) this._cache = this._parse(window.location.search);
-        return this._cache;
-    },
-};
-
-var url_parser = new UrlArgumentParser();
-
-export default {
-    UrlArgumentParser: UrlArgumentParser,
-    parameters: url_parser.get.bind(url_parser),
-};
diff --git a/src/core/url.test.js b/src/core/url.test.js
deleted file mode 100644
index 1f99fc728..000000000
--- a/src/core/url.test.js
+++ /dev/null
@@ -1,68 +0,0 @@
-import url from "./url";
-
-describe("Core / url / UrlArgumentParser", function () {
-    describe("_decodeQS", function () {
-        it("Basic string", function () {
-            var parser = new url.UrlArgumentParser();
-            expect(parser._decodeQS("Foo")).toBe("Foo");
-        });
-
-        it("String with whitespace", function () {
-            var parser = new url.UrlArgumentParser();
-            expect(parser._decodeQS("Aap+Noot+Mies")).toBe("Aap Noot Mies");
-        });
-
-        it("String with encoded characters", function () {
-            var parser = new url.UrlArgumentParser();
-            expect(parser._decodeQS("Jip%26Janneke")).toBe("Jip&Janneke");
-        });
-    });
-
-    describe("_parse", function () {
-        it("No query string", function () {
-            var parser = new url.UrlArgumentParser();
-            expect(parser._parse("")).toEqual({});
-        });
-
-        it("No parameter specified", function () {
-            var parser = new url.UrlArgumentParser();
-            expect(parser._parse("?")).toEqual({});
-        });
-
-        it("Parameter without value", function () {
-            var parser = new url.UrlArgumentParser();
-            expect(parser._parse("?key")).toEqual({ key: [null] });
-        });
-
-        it("Parameter with empty value", function () {
-            var parser = new url.UrlArgumentParser();
-            expect(parser._parse("?key=")).toEqual({ key: [""] });
-        });
-
-        it("Parameter with plain value", function () {
-            var parser = new url.UrlArgumentParser();
-            expect(parser._parse("?key=value")).toEqual({ key: ["value"] });
-        });
-
-        it("Multiple parameters", function () {
-            var parser = new url.UrlArgumentParser();
-            expect(parser._parse("?one=en&two=to")).toEqual({
-                one: ["en"],
-                two: ["to"],
-            });
-        });
-
-        it("Parameter with multiple values", function () {
-            var parser = new url.UrlArgumentParser();
-            expect(parser._parse("?key=value&key=other")).toEqual({
-                key: ["value", "other"],
-            });
-        });
-    });
-});
-
-describe("Core / url / parameters", function () {
-    it("Bound to working parser", function () {
-        expect(url.parameters()).not.toBe(undefined);
-    });
-});
diff --git a/src/pat/slides/slides.js b/src/pat/slides/slides.js
index ece5cc7f6..bf5e1ba4d 100644
--- a/src/pat/slides/slides.js
+++ b/src/pat/slides/slides.js
@@ -1,48 +1,37 @@
 /**
  * Patterns slides - Automatic and customised slideshows.
- *
- * Copyright 2013 Simplon B.V. - Wichert Akkerman
  */
 import $ from "jquery";
-import registry from "../../core/registry";
+import Base from "../../core/base";
 import utils from "../../core/utils";
-import url from "../../core/url";
-import "../../core/remove";
 
-var slides = {
+export default Base.extend({
     name: "slides",
     trigger: ".pat-slides",
 
-    setup: function () {
-        $(document).on("patterns-injected", utils.debounce(slides._reset, 100));
-    },
-
-    async init($el) {
-        if (!this.el.querySelector(".slide")) {
-            // no slides, nothing to do.
-            return;
-        }
+    async init() {
         await import("slides/src/slides"); // loads ``Presentation`` globally.
 
-        var parameters = url.parameters();
-        if (parameters.slides !== undefined) {
-            var requested_ids = slides._collapse_ids(parameters.slides);
-            if (requested_ids) slides._remove_slides($el, requested_ids);
+        const slides_filter = new URL(window.location).searchParams.get("slides");
+        if (slides_filter) {
+            const requested_ids = this._collapse_ids(slides_filter);
+            if (requested_ids) {
+                this._remove_slides(requested_ids);
+            }
         }
-        $el.each(function () {
-            var presentation = new window.Presentation(this),
-                $container = $(this);
-            $container
-                .data("pat-slide", presentation)
-                .on("SlideDisplay", slides._onSlideDisplay)
-                .on("SlideHide", slides._onSlideHide);
-        });
-        return slides._hook($el);
+        this.presentation = new window.Presentation(this.el);
+        this.$el
+            .on("SlideDisplay", this._on_slide_display.bind(this))
+            .on("SlideHide", this._on_slide_hide.bind(this));
+
+        $(document).on("patterns-injected", utils.debounce(this._reset.bind(this), 100));
+
+        this._hook();
     },
 
-    _onSlideDisplay: function (event) {
-        var slide = event.originalEvent.detail.slide.element,
-            $videos = $("video", slide);
+    _on_slide_display(event) {
+        const slide = event.originalEvent.detail.slide.element;
+        const $videos = $("video", slide);
 
         $videos.each(function () {
             if (this.paused) {
@@ -52,54 +41,40 @@ var slides = {
         });
     },
 
-    _onSlideHide: function (event) {
-        var slide = event.originalEvent.detail.slide.element,
-            $videos = $("video", slide);
+    _on_slide_hide(event) {
+        const slide = event.originalEvent.detail.slide.element;
+        const $videos = $("video", slide);
 
         $videos.each(function () {
-            if (!this.paused) this.pause();
+            if (!this.paused) {
+                this.pause();
+            }
         });
     },
 
-    _collapse_ids: function (params) {
-        var ids = [];
-        params.forEach(function (param) {
-            if (param)
-                ids = ids.concat(
-                    param.split(",").filter(function (id) {
-                        return !!id;
-                    })
-                );
-        });
-        return ids;
+    _collapse_ids(id_string) {
+        return (id_string || "").split(",").filter((it) => !!it);
     },
 
-    _remove_slides: function ($shows, ids) {
-        var has_bad_id = function (idx, el) {
-            return ids.indexOf(el.id) === -1;
-        };
-
-        for (var i = 0; i < $shows.length; i++) {
-            var $show = $shows.eq(i),
-                $bad_slides = $show.find(".slide[id]").filter(has_bad_id);
-            $bad_slides.remove();
+    _remove_slides(keep_ids) {
+        for (const slide of this.el.querySelectorAll(".slide[id]")) {
+            if (keep_ids.indexOf(slide.id) !== -1) {
+                // Not an id to remove
+                continue;
+            }
+            console.log("remove slide", slide);
+            slide.remove();
         }
     },
 
-    _hook: function ($el) {
-        return $el
+    _hook() {
+        this.$el
             .off("destroy.pat-slide")
-            .on("destroy.pat-slide", utils.debounce(slides._reset, 100));
+            .on("destroy.pat-slide", utils.debounce(this._reset.bind(this), 100));
     },
 
-    _reset: function () {
-        var $container = $(this).closest(".pat-slides"),
-            presentation = $container.data("pat-slide");
-        if (presentation) presentation.scan();
-        slides._hook($(this.trigger));
+    _reset() {
+        this.presentation.scan();
+        this._hook();
     },
-};
-
-slides.setup();
-registry.register(slides);
-export default slides;
+});
diff --git a/src/pat/slides/slides.test.js b/src/pat/slides/slides.test.js
index c9c6940c1..d160f4fe0 100644
--- a/src/pat/slides/slides.test.js
+++ b/src/pat/slides/slides.test.js
@@ -1,4 +1,4 @@
-import pattern from "./slides";
+import Pattern from "./slides";
 import $ from "jquery";
 import utils from "../../core/utils";
 import { jest } from "@jest/globals";
@@ -8,39 +8,44 @@ describe("pat-slides", function () {
         jest.restoreAllMocks();
     });
 
-    describe("_collapse_ids", function () {
+    describe("1 - _collapse_ids", function () {
         it("Single id", function () {
-            expect(pattern._collapse_ids(["foo"])).toEqual(["foo"]);
+            const instance = new Pattern(document.createElement("div"));
+            expect(instance._collapse_ids("foo")).toEqual(["foo"]);
         });
 
         it("Comma-separated list of ids", function () {
-            expect(pattern._collapse_ids(["foo,bar"])).toEqual(["foo", "bar"]);
+            const instance = new Pattern(document.createElement("div"));
+            expect(instance._collapse_ids("foo,bar")).toEqual(["foo", "bar"]);
         });
 
         it("Skip empty ids", function () {
-            expect(pattern._collapse_ids(["foo,,bar"])).toEqual(["foo", "bar"]);
+            const instance = new Pattern(document.createElement("div"));
+            expect(instance._collapse_ids("foo,,bar")).toEqual(["foo", "bar"]);
         });
 
         it("Parameter without value", function () {
-            expect(pattern._collapse_ids([null])).toEqual([]);
+            const instance = new Pattern(document.createElement("div"));
+            expect(instance._collapse_ids(null)).toEqual([]);
         });
 
         it("Parameter with empty value", function () {
-            expect(pattern._collapse_ids([""])).toEqual([]);
-        });
-
-        it("Multiple parameters", function () {
-            expect(pattern._collapse_ids(["foo", "bar"])).toEqual(["foo", "bar"]);
+            const instance = new Pattern(document.createElement("div"));
+            expect(instance._collapse_ids("")).toEqual([]);
         });
     });
 
-    describe("_remove_slides", function () {
-        it("Remove slides from DOM", function () {
-            var $show = $("<div/>", { class: "pat-slides" });
-            for (var i = 1; i <= 4; i++)
+    describe("2 - _remove_slides", function () {
+        it("Remove slides from DOM", async function () {
+            const $show = $("<div/>", { class: "pat-slides" });
+            for (let i = 1; i <= 4; i++)
                 $("<div/>", { class: "slide", id: "slide" + i }).appendTo($show);
-            pattern._remove_slides($show, ["slide1", "slide3"]);
-            var ids = $.makeArray(
+
+            const instance = new Pattern($show);
+            await utils.timeout(1); // wait a tick for async to settle.
+
+            instance._remove_slides(["slide1", "slide3"]);
+            const ids = $.makeArray(
                 $show.find(".slide").map(function (idx, el) {
                     return el.id;
                 })
@@ -48,26 +53,34 @@ describe("pat-slides", function () {
             expect(ids).toEqual(["slide1", "slide3"]);
         });
 
-        it.skip("Trigger reset when removing slides", function () {
-            var $show = $("<div/>", { class: "pat-slides" });
-            for (var i = 1; i <= 4; i++) {
+        it.skip("Trigger reset when removing slides", async function () {
+            const $show = $("<div/>", { class: "pat-slides" });
+            for (let i = 1; i <= 4; i++) {
                 $("<div/>", { class: "slide", id: "slide" + i }).appendTo($show);
             }
             jest.spyOn(utils, "debounce").mockImplementation((func) => {
                 return func;
             });
-            var spy_reset = jest.spyOn(pattern, "_reset");
-            pattern._hook($show);
-            pattern._remove_slides($show, ["slide1", "slide3"]);
+
+            const instance = new Pattern($show);
+            await utils.timeout(1); // wait a tick for async to settle.
+
+            const spy_reset = jest.spyOn(instance, "_reset");
+            instance._hook();
+            instance._remove_slides(["slide1", "slide3"]);
             expect(spy_reset).toHaveBeenCalled();
         });
 
-        it("Do not trigger reset when not doing anything", function () {
-            var $show = $("<div/>", { class: "pat-slides" });
-            for (var i = 1; i <= 2; i++)
+        it("Do not trigger reset when not doing anything", async function () {
+            const $show = $("<div/>", { class: "pat-slides" });
+            for (let i = 1; i <= 2; i++)
                 $("<div/>", { class: "slide", id: "slide" + i }).appendTo($show);
-            var spy_reset = jest.spyOn(pattern, "_reset");
-            pattern._remove_slides($show, ["slide1", "slide2"]);
+
+            const instance = new Pattern($show);
+            await utils.timeout(1); // wait a tick for async to settle.
+
+            const spy_reset = jest.spyOn(instance, "_reset");
+            instance._remove_slides(["slide1", "slide2"]);
             expect(spy_reset).not.toHaveBeenCalled();
         });
     });