diff --git a/src/ol/Collection.js b/src/ol/Collection.js
index 00376904e7..c2ae8689ad 100644
--- a/src/ol/Collection.js
+++ b/src/ol/Collection.js
@@ -160,7 +160,7 @@ class Collection extends BaseObject {
    * @api
    */
   getLength() {
-    return /** @type {number} */ (this.get(Property.LENGTH));
+    return this.get(Property.LENGTH);
   }
 
   /**
diff --git a/src/ol/Feature.js b/src/ol/Feature.js
index 752e0f096c..12cc0d0a40 100644
--- a/src/ol/Feature.js
+++ b/src/ol/Feature.js
@@ -5,8 +5,6 @@ import {assert} from './asserts.js';
 import {listen, unlisten, unlistenByKey} from './events.js';
 import EventType from './events/EventType.js';
 import BaseObject, {getChangeEventType} from './Object.js';
-import Geometry from './geom/Geometry.js';
-import Style from './style/Style.js';
 
 /**
  * @typedef {typeof Feature|typeof import("./render/Feature.js").default} FeatureClass
@@ -62,7 +60,7 @@ import Style from './style/Style.js';
  */
 class Feature extends BaseObject {
   /**
-   * @param {Geometry|Object<string, *>=} opt_geometryOrProperties
+   * @param {import("./geom/Geometry.js").default|Object<string, *>=} opt_geometryOrProperties
    *     You may pass a Geometry object directly, or an object literal containing
    *     properties. If you pass an object literal, you may include a Geometry
    *     associated with a `geometry` key.
@@ -86,7 +84,7 @@ class Feature extends BaseObject {
     /**
      * User provided style.
      * @private
-     * @type {Style|Array<Style>|import("./style/Style.js").StyleFunction}
+     * @type {import("./style/Style.js").StyleLike}
      */
     this.style_ = null;
 
@@ -106,10 +104,9 @@ class Feature extends BaseObject {
       this, getChangeEventType(this.geometryName_),
       this.handleGeometryChanged_, this);
 
-    if (opt_geometryOrProperties !== undefined) {
-      if (opt_geometryOrProperties instanceof Geometry) {
-
-        const geometry = /** @type {Geometry} */ (opt_geometryOrProperties);
+    if (opt_geometryOrProperties) {
+      if (typeof /** @type {?} */ (opt_geometryOrProperties).getSimplifiedGeometry === 'function') {
+        const geometry = /** @type {import("./geom/Geometry.js").default} */ (opt_geometryOrProperties);
         this.setGeometry(geometry);
       } else {
         /** @type {Object<string, *>} */
@@ -143,13 +140,13 @@ class Feature extends BaseObject {
    * Get the feature's default geometry.  A feature may have any number of named
    * geometries.  The "default" geometry (the one that is rendered by default) is
    * set when calling {@link module:ol/Feature~Feature#setGeometry}.
-   * @return {Geometry|undefined} The default geometry for the feature.
+   * @return {import("./geom/Geometry.js").default|undefined} The default geometry for the feature.
    * @api
    * @observable
    */
   getGeometry() {
     return (
-      /** @type {Geometry|undefined} */ (this.get(this.geometryName_))
+      /** @type {import("./geom/Geometry.js").default|undefined} */ (this.get(this.geometryName_))
     );
   }
 
@@ -178,7 +175,7 @@ class Feature extends BaseObject {
   /**
    * Get the feature's style. Will return what was provided to the
    * {@link module:ol/Feature~Feature#setStyle} method.
-   * @return {Style|Array<Style>|import("./style/Style.js").StyleFunction} The feature style.
+   * @return {import("./style/Style.js").StyleLike} The feature style.
    * @api
    */
   getStyle() {
@@ -221,7 +218,7 @@ class Feature extends BaseObject {
   /**
    * Set the default geometry for the feature.  This will update the property
    * with the name returned by {@link module:ol/Feature~Feature#getGeometryName}.
-   * @param {Geometry|undefined} geometry The new geometry.
+   * @param {import("./geom/Geometry.js").default|undefined} geometry The new geometry.
    * @api
    * @observable
    */
@@ -233,7 +230,7 @@ class Feature extends BaseObject {
    * Set the style for the feature.  This can be a single style object, an array
    * of styles, or a function that takes a resolution and returns an array of
    * styles. If it is `null` the feature has no style (a `null` style).
-   * @param {Style|Array<Style>|import("./style/Style.js").StyleFunction} style Style for this feature.
+   * @param {import("./style/Style.js").StyleLike} style Style for this feature.
    * @api
    * @fires module:ol/events/Event~Event#event:change
    */
@@ -281,7 +278,7 @@ class Feature extends BaseObject {
  * Convert the provided object into a feature style function.  Functions passed
  * through unchanged.  Arrays of Style or single style objects wrapped
  * in a new feature style function.
- * @param {import("./style/Style.js").StyleFunction|!Array<Style>|!Style} obj
+ * @param {!import("./style/Style.js").StyleFunction|!Array<import("./style/Style.js").default>|!import("./style/Style.js").default} obj
  *     A feature style function, a single style, or an array of styles.
  * @return {import("./style/Style.js").StyleFunction} A style function.
  */
@@ -290,15 +287,16 @@ export function createStyleFunction(obj) {
     return obj;
   } else {
     /**
-     * @type {Array<Style>}
+     * @type {Array<import("./style/Style.js").default>}
      */
     let styles;
     if (Array.isArray(obj)) {
       styles = obj;
     } else {
-      assert(obj instanceof Style,
+      assert(typeof /** @type {?} */ (obj).getZIndex === 'function',
         41); // Expected an `import("./style/Style.js").Style` or an array of `import("./style/Style.js").Style`
-      styles = [obj];
+      const style = /** @type {import("./style/Style.js").default} */ (obj);
+      styles = [style];
     }
     return function() {
       return styles;
diff --git a/src/ol/ImageTile.js b/src/ol/ImageTile.js
index 55a292af6b..a5ae93b667 100644
--- a/src/ol/ImageTile.js
+++ b/src/ol/ImageTile.js
@@ -109,8 +109,8 @@ class ImageTile extends Tile {
    * @private
    */
   handleImageLoad_() {
-    if (this.image_ instanceof HTMLImageElement &&
-      this.image_.naturalWidth && this.image_.naturalHeight) {
+    const image = /** @type {HTMLImageElement} */ (this.image_);
+    if (image.naturalWidth && image.naturalHeight) {
       this.state = TileState.LOADED;
     } else {
       this.state = TileState.EMPTY;
diff --git a/src/ol/PluggableMap.js b/src/ol/PluggableMap.js
index 5a38a7163d..0f231b3b49 100644
--- a/src/ol/PluggableMap.js
+++ b/src/ol/PluggableMap.js
@@ -102,7 +102,7 @@ import {create as createTransform, apply as applyTransform} from './transform.js
  * map target (i.e. the user-provided div for the map). If this is not
  * `document`, the target element needs to be focused for key events to be
  * emitted, requiring that the target element has a `tabindex` attribute.
- * @property {Array<import("./layer/Base.js").default>|Collection<import("./layer/Base.js").default>} [layers]
+ * @property {Array<import("./layer/Base.js").default>|Collection<import("./layer/Base.js").default>|LayerGroup} [layers]
  * Layers. If this is not defined, a map with no layers will be rendered. Note
  * that layers are rendered in the order supplied, so if you want, for example,
  * a vector layer to appear on top of a tile layer, it must come after the tile
@@ -1368,8 +1368,8 @@ function createOptionsInternal(options) {
    */
   const values = {};
 
-  const layerGroup = (options.layers instanceof LayerGroup) ?
-    options.layers : new LayerGroup({layers: options.layers});
+  const layerGroup = options.layers && typeof /** @type {?} */ (options.layers).getLayers === 'function' ?
+    /** @type {LayerGroup} */ (options.layers) : new LayerGroup({layers: /** @type {Collection} */ (options.layers)});
   values[MapProperty.LAYERGROUP] = layerGroup;
 
   values[MapProperty.TARGET] = options.target;
@@ -1382,9 +1382,9 @@ function createOptionsInternal(options) {
     if (Array.isArray(options.controls)) {
       controls = new Collection(options.controls.slice());
     } else {
-      assert(options.controls instanceof Collection,
+      assert(typeof /** @type {?} */ (options.controls).getArray === 'function',
         47); // Expected `controls` to be an array or an `import("./Collection.js").Collection`
-      controls = options.controls;
+      controls = /** @type {Collection} */ (options.controls);
     }
   }
 
@@ -1393,9 +1393,9 @@ function createOptionsInternal(options) {
     if (Array.isArray(options.interactions)) {
       interactions = new Collection(options.interactions.slice());
     } else {
-      assert(options.interactions instanceof Collection,
+      assert(typeof /** @type {?} */ (options.interactions).getArray === 'function',
         48); // Expected `interactions` to be an array or an `import("./Collection.js").Collection`
-      interactions = options.interactions;
+      interactions = /** @type {Collection} */ (options.interactions);
     }
   }
 
@@ -1404,7 +1404,7 @@ function createOptionsInternal(options) {
     if (Array.isArray(options.overlays)) {
       overlays = new Collection(options.overlays.slice());
     } else {
-      assert(options.overlays instanceof Collection,
+      assert(typeof /** @type {?} */ (options.overlays).getArray === 'function',
         49); // Expected `overlays` to be an array or an `import("./Collection.js").Collection`
       overlays = options.overlays;
     }
@@ -1430,8 +1430,8 @@ export default PluggableMap;
 function getLoading(layers) {
   for (let i = 0, ii = layers.length; i < ii; ++i) {
     const layer = layers[i];
-    if (layer instanceof LayerGroup) {
-      return getLoading(layer.getLayers().getArray());
+    if (typeof /** @type {?} */ (layer).getLayers === 'function') {
+      return getLoading(/** @type {LayerGroup} */ (layer).getLayers().getArray());
     } else {
       const source = /** @type {import("./layer/Layer.js").default} */ (
         layer).getSource();
diff --git a/src/ol/View.js b/src/ol/View.js
index eb6b1a98a9..303934ac94 100644
--- a/src/ol/View.js
+++ b/src/ol/View.js
@@ -17,7 +17,6 @@ import {inAndOut} from './easing.js';
 import {getForViewAndSize, getCenter, getHeight, getWidth, isEmpty} from './extent.js';
 import GeometryType from './geom/GeometryType.js';
 import {fromExtent as polygonFromExtent} from './geom/Polygon.js';
-import SimpleGeometry from './geom/SimpleGeometry.js';
 import {clamp, modulo} from './math.js';
 import {assign} from './obj.js';
 import {createProjection, METERS_PER_UNIT} from './proj.js';
@@ -974,7 +973,7 @@ class View extends BaseObject {
    * The size is pixel dimensions of the box to fit the extent into.
    * In most cases you will want to use the map size, that is `map.getSize()`.
    * Takes care of the map angle.
-   * @param {SimpleGeometry|import("./extent.js").Extent} geometryOrExtent The geometry or
+   * @param {import("./geom/SimpleGeometry.js").default|import("./extent.js").Extent} geometryOrExtent The geometry or
    *     extent to fit the view to.
    * @param {FitOptions=} opt_options Options.
    * @api
@@ -985,11 +984,11 @@ class View extends BaseObject {
     if (!size) {
       size = this.getSizeFromViewport_();
     }
-    /** @type {SimpleGeometry} */
+    /** @type {import("./geom/SimpleGeometry.js").default} */
     let geometry;
-    if (!(geometryOrExtent instanceof SimpleGeometry)) {
-      assert(Array.isArray(geometryOrExtent),
-        24); // Invalid extent or geometry provided as `geometry`
+    assert(Array.isArray(geometryOrExtent) || typeof /** @type {?} */ (geometryOrExtent).getSimplifiedGeometry === 'function',
+      24); // Invalid extent or geometry provided as `geometry`
+    if (Array.isArray(geometryOrExtent)) {
       assert(!isEmpty(geometryOrExtent),
         25); // Cannot fit empty extent provided as `geometry`
       geometry = polygonFromExtent(geometryOrExtent);
diff --git a/src/ol/color.js b/src/ol/color.js
index 16572846b3..b48f149e90 100644
--- a/src/ol/color.js
+++ b/src/ol/color.js
@@ -133,7 +133,7 @@ export function asArray(color) {
   if (Array.isArray(color)) {
     return color;
   } else {
-    return fromString(/** @type {string} */ (color));
+    return fromString(color);
   }
 }
 
@@ -185,9 +185,7 @@ function fromStringInternal_(s) {
   } else {
     assert(false, 14); // Invalid color
   }
-  return (
-    /** @type {Color} */ (color)
-  );
+  return color;
 }
 
 
diff --git a/src/ol/colorlike.js b/src/ol/colorlike.js
index ead3b2ccda..ddeeb7d3ad 100644
--- a/src/ol/colorlike.js
+++ b/src/ol/colorlike.js
@@ -23,22 +23,9 @@ import {toString} from './color.js';
  * @api
  */
 export function asColorLike(color) {
-  if (isColorLike(color)) {
-    return /** @type {string|CanvasPattern|CanvasGradient} */ (color);
+  if (Array.isArray(color)) {
+    return toString(color);
   } else {
-    return toString(/** @type {import("./color.js").Color} */ (color));
+    return color;
   }
 }
-
-
-/**
- * @param {?} color The value that is potentially an {@link ol/colorlike~ColorLike}.
- * @return {boolean} The color is an {@link ol/colorlike~ColorLike}.
- */
-export function isColorLike(color) {
-  return (
-    typeof color === 'string' ||
-    color instanceof CanvasPattern ||
-    color instanceof CanvasGradient
-  );
-}
diff --git a/src/ol/events/condition.js b/src/ol/events/condition.js
index a1dfc7151d..673eae29bc 100644
--- a/src/ol/events/condition.js
+++ b/src/ol/events/condition.js
@@ -2,7 +2,6 @@
  * @module ol/events/condition
  */
 import MapBrowserEventType from '../MapBrowserEventType.js';
-import MapBrowserPointerEvent from '../MapBrowserPointerEvent.js';
 import {assert} from '../asserts.js';
 import {TRUE, FALSE} from '../functions.js';
 import {WEBKIT, MAC} from '../has.js';
@@ -225,9 +224,10 @@ export const targetNotEditable = function(mapBrowserEvent) {
  * @api
  */
 export const mouseOnly = function(mapBrowserEvent) {
-  assert(mapBrowserEvent instanceof MapBrowserPointerEvent, 56); // mapBrowserEvent must originate from a pointer event
+  const pointerEvent = /** @type {import("../MapBrowserPointerEvent").default} */ (mapBrowserEvent).pointerEvent;
+  assert(pointerEvent !== undefined, 56); // mapBrowserEvent must originate from a pointer event
   // see http://www.w3.org/TR/pointerevents/#widl-PointerEvent-pointerType
-  return /** @type {MapBrowserPointerEvent} */ (mapBrowserEvent).pointerEvent.pointerType == 'mouse';
+  return pointerEvent.pointerType == 'mouse';
 };
 
 
@@ -241,7 +241,7 @@ export const mouseOnly = function(mapBrowserEvent) {
  * @api
  */
 export const primaryAction = function(mapBrowserEvent) {
-  assert(mapBrowserEvent instanceof MapBrowserPointerEvent, 56); // mapBrowserEvent must originate from a pointer event
-  const pointerEvent = /** @type {MapBrowserPointerEvent} */ (mapBrowserEvent).pointerEvent;
+  const pointerEvent = /** @type {import("../MapBrowserPointerEvent").default} */ (mapBrowserEvent).pointerEvent;
+  assert(pointerEvent !== undefined, 56); // mapBrowserEvent must originate from a pointer event
   return pointerEvent.isPrimary && pointerEvent.button === 0;
 };
diff --git a/src/ol/extent.js b/src/ol/extent.js
index 1ae333ba3c..9858190746 100644
--- a/src/ol/extent.js
+++ b/src/ol/extent.js
@@ -494,9 +494,7 @@ export function getCorner(extent, corner) {
   } else {
     assert(false, 13); // Invalid corner
   }
-  return (
-    /** @type {!import("./coordinate.js").Coordinate} */ (coordinate)
-  );
+  return coordinate;
 }
 
 
diff --git a/src/ol/featureloader.js b/src/ol/featureloader.js
index 668dad7117..dce9c2acba 100644
--- a/src/ol/featureloader.js
+++ b/src/ol/featureloader.js
@@ -3,7 +3,6 @@
  */
 import {VOID} from './functions.js';
 import FormatType from './format/FormatType.js';
-import VectorSource from './source/Vector';
 
 /**
  * {@link module:ol/source/Vector} sources use a function of this type to
@@ -17,7 +16,7 @@ import VectorSource from './source/Vector';
  *
  * The function is responsible for loading the features and adding them to the
  * source.
- * @typedef {function(this:(VectorSource|import("./VectorTile.js").default), import("./extent.js").Extent, number,
+ * @typedef {function(this:(import("./source/Vector").default|import("./VectorTile.js").default), import("./extent.js").Extent, number,
  *                    import("./proj/Projection.js").default)} FeatureLoader
  * @api
  */
@@ -39,10 +38,10 @@ import VectorSource from './source/Vector';
 /**
  * @param {string|FeatureUrlFunction} url Feature URL service.
  * @param {import("./format/Feature.js").default} format Feature format.
- * @param {function(this:import("./VectorTile.js").default, Array<import("./Feature.js").default>, import("./proj/Projection.js").default, import("./extent.js").Extent)|function(this:VectorSource, Array<import("./Feature.js").default>)} success
+ * @param {function(this:import("./VectorTile.js").default, Array<import("./Feature.js").default>, import("./proj/Projection.js").default, import("./extent.js").Extent)|function(this:import("./source/Vector").default, Array<import("./Feature.js").default>)} success
  *     Function called with the loaded features and optionally with the data
  *     projection. Called with the vector tile or source as `this`.
- * @param {function(this:import("./VectorTile.js").default)|function(this:VectorSource)} failure
+ * @param {function(this:import("./VectorTile.js").default)|function(this:import("./source/Vector").default)} failure
  *     Function called when loading failed. Called with the vector tile or
  *     source as `this`.
  * @return {FeatureLoader} The feature loader.
@@ -53,7 +52,7 @@ export function loadFeaturesXhr(url, format, success, failure) {
      * @param {import("./extent.js").Extent} extent Extent.
      * @param {number} resolution Resolution.
      * @param {import("./proj/Projection.js").default} projection Projection.
-     * @this {VectorSource|import("./VectorTile.js").default}
+     * @this {import("./source/Vector").default|import("./VectorTile.js").default}
      */
     function(extent, resolution, projection) {
       const xhr = new XMLHttpRequest();
@@ -121,11 +120,12 @@ export function xhr(url, format) {
      * @param {Array<import("./Feature.js").default>} features The loaded features.
      * @param {import("./proj/Projection.js").default} dataProjection Data
      * projection.
-     * @this {VectorSource|import("./VectorTile.js").default}
+     * @this {import("./source/Vector").default|import("./VectorTile.js").default}
      */
     function(features, dataProjection) {
-      if (this instanceof VectorSource) {
-        this.addFeatures(features);
+      const sourceOrTile = /** @type {?} */ (this);
+      if (typeof sourceOrTile.addFeatures === 'function') {
+        /** @type {import("./source/Vector").default} */ (sourceOrTile).addFeatures(features);
       }
     }, /* FIXME handle error */ VOID);
 }
diff --git a/src/ol/format/Feature.js b/src/ol/format/Feature.js
index 17b976f702..4e3c20be15 100644
--- a/src/ol/format/Feature.js
+++ b/src/ol/format/Feature.js
@@ -1,7 +1,6 @@
 /**
  * @module ol/format/Feature
  */
-import Geometry from '../geom/Geometry.js';
 import {assign} from '../obj.js';
 import {get as getProjection, equivalent as equivalentProjection, transformExtent} from '../proj.js';
 
@@ -151,7 +150,7 @@ class FeatureFormat {
    * @abstract
    * @param {Document|Node|Object|string} source Source.
    * @param {ReadOptions=} opt_options Read options.
-   * @return {Geometry} Geometry.
+   * @return {import("../geom/Geometry.js").default} Geometry.
    */
   readGeometry(source, opt_options) {}
 
@@ -188,7 +187,7 @@ class FeatureFormat {
    * Write a single geometry in this format.
    *
    * @abstract
-   * @param {Geometry} geometry Geometry.
+   * @param {import("../geom/Geometry.js").default} geometry Geometry.
    * @param {WriteOptions=} opt_options Write options.
    * @return {string} Result.
    */
@@ -198,10 +197,10 @@ class FeatureFormat {
 export default FeatureFormat;
 
 /**
- * @param {Geometry|import("../extent.js").Extent} geometry Geometry.
+ * @param {import("../geom/Geometry.js").default|import("../extent.js").Extent} geometry Geometry.
  * @param {boolean} write Set to true for writing, false for reading.
  * @param {(WriteOptions|ReadOptions)=} opt_options Options.
- * @return {Geometry|import("../extent.js").Extent} Transformed geometry.
+ * @return {import("../geom/Geometry.js").default|import("../extent.js").Extent} Transformed geometry.
  */
 export function transformWithOptions(geometry, write, opt_options) {
   const featureProjection = opt_options ?
@@ -209,28 +208,28 @@ export function transformWithOptions(geometry, write, opt_options) {
   const dataProjection = opt_options ?
     getProjection(opt_options.dataProjection) : null;
   /**
-   * @type {Geometry|import("../extent.js").Extent}
+   * @type {import("../geom/Geometry.js").default|import("../extent.js").Extent}
    */
   let transformed;
   if (featureProjection && dataProjection &&
       !equivalentProjection(featureProjection, dataProjection)) {
-    if (geometry instanceof Geometry) {
-      transformed = (write ? geometry.clone() : geometry).transform(
-        write ? featureProjection : dataProjection,
-        write ? dataProjection : featureProjection);
-    } else {
+    if (Array.isArray(geometry)) {
       // FIXME this is necessary because GML treats extents
       // as geometries
       transformed = transformExtent(
         geometry,
         dataProjection,
         featureProjection);
+    } else {
+      transformed = (write ? /** @type {import("../geom/Geometry").default} */ (geometry).clone() : geometry).transform(
+        write ? featureProjection : dataProjection,
+        write ? dataProjection : featureProjection);
     }
   } else {
     transformed = geometry;
   }
   if (write && opt_options && /** @type {WriteOptions} */ (opt_options).decimals !== undefined &&
-    transformed instanceof Geometry) {
+    !Array.isArray(transformed)) {
     const power = Math.pow(10, /** @type {WriteOptions} */ (opt_options).decimals);
     // if decimals option on write, round each coordinate appropriately
     /**
@@ -244,7 +243,7 @@ export function transformWithOptions(geometry, write, opt_options) {
       return coordinates;
     };
     if (transformed === geometry) {
-      transformed = transformed.clone();
+      transformed = /** @type {import("../geom/Geometry").default} */ (geometry).clone();
     }
     transformed.applyTransform(transform);
   }
diff --git a/src/ol/format/GML2.js b/src/ol/format/GML2.js
index 313bf83535..81f1214c8b 100644
--- a/src/ol/format/GML2.js
+++ b/src/ol/format/GML2.js
@@ -5,7 +5,6 @@ import {createOrUpdate} from '../extent.js';
 import {transformWithOptions} from '../format/Feature.js';
 import GMLBase, {GMLNS} from '../format/GMLBase.js';
 import {writeStringTextNode} from '../format/xsd.js';
-import Geometry from '../geom/Geometry.js';
 import {assign} from '../obj.js';
 import {get as getProjection, transformExtent} from '../proj.js';
 import {createElementNS, getAllTextContent, makeArrayPusher, makeChildAppender,
@@ -196,7 +195,7 @@ class GML2 extends GMLBase {
       if (value !== null) {
         keys.push(key);
         values.push(value);
-        if (key == geometryName || value instanceof Geometry) {
+        if (key == geometryName || typeof /** @type {?} */ (value).getSimplifiedGeometry === 'function') {
           if (!(key in context.serializers[featureNS])) {
             context.serializers[featureNS][key] = makeChildAppender(
               this.writeGeometryElement, this);
diff --git a/src/ol/format/GML3.js b/src/ol/format/GML3.js
index 276d7b2e73..c4cf3d08d4 100644
--- a/src/ol/format/GML3.js
+++ b/src/ol/format/GML3.js
@@ -6,7 +6,6 @@ import {createOrUpdate} from '../extent.js';
 import {transformWithOptions} from '../format/Feature.js';
 import GMLBase, {GMLNS} from '../format/GMLBase.js';
 import {readNonNegativeIntegerString, writeStringTextNode} from '../format/xsd.js';
-import Geometry from '../geom/Geometry.js';
 import GeometryLayout from '../geom/GeometryLayout.js';
 import LineString from '../geom/LineString.js';
 import MultiLineString from '../geom/MultiLineString.js';
@@ -774,7 +773,7 @@ class GML3 extends GMLBase {
       if (value !== null) {
         keys.push(key);
         values.push(value);
-        if (key == geometryName || value instanceof Geometry) {
+        if (key == geometryName || typeof /** @type {?} */ (value).getSimplifiedGeometry === 'function') {
           if (!(key in context.serializers[featureNS])) {
             context.serializers[featureNS][key] = makeChildAppender(
               this.writeGeometryElement, this);
diff --git a/src/ol/format/GPX.js b/src/ol/format/GPX.js
index 58a2814208..c90ff72990 100644
--- a/src/ol/format/GPX.js
+++ b/src/ol/format/GPX.js
@@ -7,6 +7,7 @@ import {transformWithOptions} from '../format/Feature.js';
 import XMLFeature from '../format/XMLFeature.js';
 import {readString, readDecimal, readNonNegativeInteger, readDateTime, writeStringTextNode, writeNonNegativeIntegerTextNode, writeDecimalTextNode, writeDateTimeTextNode} from '../format/xsd.js';
 import GeometryLayout from '../geom/GeometryLayout.js';
+import GeometryType from '../geom/GeometryType.js';
 import LineString from '../geom/LineString.js';
 import MultiLineString from '../geom/MultiLineString.js';
 import Point from '../geom/Point.js';
@@ -782,7 +783,7 @@ function writeRte(node, feature, objectStack) {
   const context = {node: node};
   context['properties'] = properties;
   const geometry = feature.getGeometry();
-  if (geometry instanceof LineString) {
+  if (geometry.getType() == GeometryType.LINE_STRING) {
     const lineString = /** @type {LineString} */ (transformWithOptions(geometry, true, options));
     context['geometryLayout'] = lineString.getLayout();
     properties['rtept'] = lineString.getCoordinates();
@@ -808,7 +809,7 @@ function writeTrk(node, feature, objectStack) {
   const context = {node: node};
   context['properties'] = properties;
   const geometry = feature.getGeometry();
-  if (geometry instanceof MultiLineString) {
+  if (geometry.getType() == GeometryType.MULTI_LINE_STRING) {
     const multiLineString = /** @type {MultiLineString} */ (transformWithOptions(geometry, true, options));
     properties['trkseg'] = multiLineString.getLineStrings();
   }
@@ -847,7 +848,7 @@ function writeWpt(node, feature, objectStack) {
   const context = objectStack[objectStack.length - 1];
   context['properties'] = feature.getProperties();
   const geometry = feature.getGeometry();
-  if (geometry instanceof Point) {
+  if (geometry.getType() == GeometryType.POINT) {
     const point = /** @type {Point} */ (transformWithOptions(geometry, true, options));
     context['geometryLayout'] = point.getLayout();
     writeWptType(node, point.getCoordinates(), objectStack);
diff --git a/src/ol/format/KML.js b/src/ol/format/KML.js
index 35c412f48e..28a27ab7f6 100644
--- a/src/ol/format/KML.js
+++ b/src/ol/format/KML.js
@@ -26,7 +26,7 @@ import IconOrigin from '../style/IconOrigin.js';
 import Stroke from '../style/Stroke.js';
 import Style from '../style/Style.js';
 import Text from '../style/Text.js';
-import {createElementNS, getAllTextContent, isDocument, isNode, makeArrayExtender,
+import {createElementNS, getAllTextContent, isDocument, makeArrayExtender,
   makeArrayPusher, makeChildAppender, makeObjectPropertySetter,
   makeReplacer, makeSequence, makeSimpleNodeFactory, makeStructureNS,
   OBJECT_PROPERTY_NODE_FACTORY, parse, parseNode, pushParseAndPop,
@@ -639,15 +639,15 @@ class KML extends XMLFeature {
    * @api
    */
   readName(source) {
-    if (isDocument(source)) {
-      return this.readNameFromDocument(/** @type {Document} */ (source));
-    } else if (isNode(source)) {
-      return this.readNameFromNode(/** @type {Element} */ (source));
+    if (!source) {
+      return undefined;
     } else if (typeof source === 'string') {
       const doc = parse(source);
       return this.readNameFromDocument(doc);
+    } else if (isDocument(source)) {
+      return this.readNameFromDocument(/** @type {Document} */ (source));
     } else {
-      return undefined;
+      return this.readNameFromNode(/** @type {Element} */ (source));
     }
   }
 
@@ -703,15 +703,15 @@ class KML extends XMLFeature {
    */
   readNetworkLinks(source) {
     const networkLinks = [];
-    if (isDocument(source)) {
-      extend(networkLinks, this.readNetworkLinksFromDocument(
-        /** @type {Document} */ (source)));
-    } else if (isNode(source)) {
-      extend(networkLinks, this.readNetworkLinksFromNode(
-        /** @type {Element} */ (source)));
-    } else if (typeof source === 'string') {
+    if (typeof source === 'string') {
       const doc = parse(source);
       extend(networkLinks, this.readNetworkLinksFromDocument(doc));
+    } else if (isDocument(source)) {
+      extend(networkLinks, this.readNetworkLinksFromDocument(
+        /** @type {Document} */ (source)));
+    } else {
+      extend(networkLinks, this.readNetworkLinksFromNode(
+        /** @type {Element} */ (source)));
     }
     return networkLinks;
   }
@@ -765,15 +765,15 @@ class KML extends XMLFeature {
    */
   readRegion(source) {
     const regions = [];
-    if (isDocument(source)) {
-      extend(regions, this.readRegionFromDocument(
-        /** @type {Document} */ (source)));
-    } else if (isNode(source)) {
-      extend(regions, this.readRegionFromNode(
-        /** @type {Element} */ (source)));
-    } else if (typeof source === 'string') {
+    if (typeof source === 'string') {
       const doc = parse(source);
       extend(regions, this.readRegionFromDocument(doc));
+    } else if (isDocument(source)) {
+      extend(regions, this.readRegionFromDocument(
+        /** @type {Document} */ (source)));
+    } else {
+      extend(regions, this.readRegionFromNode(
+        /** @type {Element} */ (source)));
     }
     return regions;
   }
@@ -2897,7 +2897,7 @@ function writeStyle(node, style, objectStack) {
   const strokeStyle = style.getStroke();
   const imageStyle = style.getImage();
   const textStyle = style.getText();
-  if (imageStyle instanceof Icon) {
+  if (imageStyle && typeof /** @type {?} */ (imageStyle).getSrc === 'function') {
     properties['IconStyle'] = imageStyle;
   }
   if (textStyle) {
diff --git a/src/ol/format/WFS.js b/src/ol/format/WFS.js
index 4d9ee2b5be..d1dab0d619 100644
--- a/src/ol/format/WFS.js
+++ b/src/ol/format/WFS.js
@@ -8,10 +8,9 @@ import GMLBase, {GMLNS} from '../format/GMLBase.js';
 import {and as andFilter, bbox as bboxFilter} from '../format/filter.js';
 import XMLFeature from '../format/XMLFeature.js';
 import {readNonNegativeIntegerString, readNonNegativeInteger, writeStringTextNode} from '../format/xsd.js';
-import Geometry from '../geom/Geometry.js';
 import {assign} from '../obj.js';
 import {get as getProjection} from '../proj.js';
-import {createElementNS, isDocument, isNode, makeArrayPusher, makeChildAppender,
+import {createElementNS, isDocument, makeArrayPusher, makeChildAppender,
   makeObjectPropertySetter, makeSimpleNodeFactory, parse, parseNode,
   pushParseAndPop, pushSerializeAndPop, XML_SCHEMA_INSTANCE_URI} from '../xml.js';
 
@@ -288,16 +287,16 @@ class WFS extends XMLFeature {
    * @api
    */
   readTransactionResponse(source) {
-    if (isDocument(source)) {
-      return this.readTransactionResponseFromDocument(
-        /** @type {Document} */ (source));
-    } else if (isNode(source)) {
-      return this.readTransactionResponseFromNode(/** @type {Element} */ (source));
+    if (!source) {
+      return undefined;
     } else if (typeof source === 'string') {
       const doc = parse(source);
       return this.readTransactionResponseFromDocument(doc);
+    } else if (isDocument(source)) {
+      return this.readTransactionResponseFromDocument(
+        /** @type {Document} */ (source));
     } else {
-      return undefined;
+      return this.readTransactionResponseFromNode(/** @type {Element} */ (source));
     }
   }
 
@@ -310,17 +309,17 @@ class WFS extends XMLFeature {
    * @api
    */
   readFeatureCollectionMetadata(source) {
-    if (isDocument(source)) {
-      return this.readFeatureCollectionMetadataFromDocument(
-        /** @type {Document} */ (source));
-    } else if (isNode(source)) {
-      return this.readFeatureCollectionMetadataFromNode(
-        /** @type {Element} */ (source));
+    if (!source) {
+      return undefined;
     } else if (typeof source === 'string') {
       const doc = parse(source);
       return this.readFeatureCollectionMetadataFromDocument(doc);
+    } else if (isDocument(source)) {
+      return this.readFeatureCollectionMetadataFromDocument(
+        /** @type {Document} */ (source));
     } else {
-      return undefined;
+      return this.readFeatureCollectionMetadataFromNode(
+        /** @type {Element} */ (source));
     }
   }
 
@@ -694,7 +693,7 @@ function writeUpdate(node, feature, objectStack) {
       const value = feature.get(keys[i]);
       if (value !== undefined) {
         let name = keys[i];
-        if (value instanceof Geometry) {
+        if (value && typeof /** @type {?} */ (value).getSimplifiedGeometry === 'function') {
           name = geometryName;
         }
         values.push({name: name, value: value});
@@ -725,7 +724,7 @@ function writeProperty(node, pair, objectStack) {
   if (pair.value !== undefined && pair.value !== null) {
     const value = createElementNS(WFSNS, 'Value');
     node.appendChild(value);
-    if (pair.value instanceof Geometry) {
+    if (pair.value && typeof /** @type {?} */ (pair.value).getSimplifiedGeometry === 'function') {
       if (gmlVersion === 2) {
         GML2.prototype.writeGeometryElement(value,
           pair.value, objectStack);
diff --git a/src/ol/format/WKT.js b/src/ol/format/WKT.js
index 5bc2422cb6..eb390212f8 100644
--- a/src/ol/format/WKT.js
+++ b/src/ol/format/WKT.js
@@ -13,7 +13,6 @@ import MultiPoint from '../geom/MultiPoint.js';
 import MultiPolygon from '../geom/MultiPolygon.js';
 import Point from '../geom/Point.js';
 import Polygon from '../geom/Polygon.js';
-import SimpleGeometry from '../geom/SimpleGeometry.js';
 
 
 /**
@@ -823,7 +822,7 @@ function encodeMultiPolygonGeometry(geom) {
 }
 
 /**
- * @param {SimpleGeometry} geom SimpleGeometry geometry.
+ * @param {import("../geom/SimpleGeometry.js").default} geom SimpleGeometry geometry.
  * @return {string} Potential dimensional information for WKT type.
  */
 function encodeGeometryLayout(geom) {
@@ -856,7 +855,7 @@ const GeometryEncoder = {
 
 /**
  * Encode a geometry as WKT.
- * @param {import("../geom/Geometry.js").default} geom The geometry to encode.
+ * @param {!import("../geom/Geometry.js").default} geom The geometry to encode.
  * @return {string} WKT string for the geometry.
  */
 function encode(geom) {
@@ -864,8 +863,8 @@ function encode(geom) {
   const geometryEncoder = GeometryEncoder[type];
   const enc = geometryEncoder(geom);
   type = type.toUpperCase();
-  if (geom instanceof SimpleGeometry) {
-    const dimInfo = encodeGeometryLayout(geom);
+  if (typeof /** @type {?} */ (geom).getFlatCoordinates === 'function') {
+    const dimInfo = encodeGeometryLayout(/** @type {import("../geom/SimpleGeometry.js").default} */ (geom));
     if (dimInfo.length > 0) {
       type += ' ' + dimInfo;
     }
diff --git a/src/ol/format/XML.js b/src/ol/format/XML.js
index 6a590a0a33..7ad822275c 100644
--- a/src/ol/format/XML.js
+++ b/src/ol/format/XML.js
@@ -1,7 +1,7 @@
 /**
  * @module ol/format/XML
  */
-import {isDocument, isNode, parse} from '../xml.js';
+import {isDocument, parse} from '../xml.js';
 
 /**
  * @classdesc
@@ -18,15 +18,15 @@ class XML {
    * @api
    */
   read(source) {
-    if (isDocument(source)) {
-      return this.readFromDocument(/** @type {Document} */ (source));
-    } else if (isNode(source)) {
-      return this.readFromNode(/** @type {Element} */ (source));
+    if (!source) {
+      return null;
     } else if (typeof source === 'string') {
       const doc = parse(source);
       return this.readFromDocument(doc);
+    } else if (isDocument(source)) {
+      return this.readFromDocument(/** @type {Document} */ (source));
     } else {
-      return null;
+      return this.readFromNode(/** @type {Element} */ (source));
     }
   }
 
diff --git a/src/ol/format/XMLFeature.js b/src/ol/format/XMLFeature.js
index feb5007419..ba03bf0cf9 100644
--- a/src/ol/format/XMLFeature.js
+++ b/src/ol/format/XMLFeature.js
@@ -4,7 +4,7 @@
 import {extend} from '../array.js';
 import FeatureFormat from '../format/Feature.js';
 import FormatType from '../format/FormatType.js';
-import {isDocument, isNode, parse} from '../xml.js';
+import {isDocument, parse} from '../xml.js';
 
 /**
  * @classdesc
@@ -41,15 +41,15 @@ class XMLFeature extends FeatureFormat {
    * @api
    */
   readFeature(source, opt_options) {
-    if (isDocument(source)) {
-      return this.readFeatureFromDocument(/** @type {Document} */ (source), opt_options);
-    } else if (isNode(source)) {
-      return this.readFeatureFromNode(/** @type {Node} */ (source), opt_options);
+    if (!source) {
+      return null;
     } else if (typeof source === 'string') {
       const doc = parse(source);
       return this.readFeatureFromDocument(doc, opt_options);
+    } else if (isDocument(source)) {
+      return this.readFeatureFromDocument(/** @type {Document} */ (source), opt_options);
     } else {
-      return null;
+      return this.readFeatureFromNode(/** @type {Node} */ (source), opt_options);
     }
   }
 
@@ -85,16 +85,16 @@ class XMLFeature extends FeatureFormat {
    * @api
    */
   readFeatures(source, opt_options) {
-    if (isDocument(source)) {
-      return this.readFeaturesFromDocument(
-        /** @type {Document} */ (source), opt_options);
-    } else if (isNode(source)) {
-      return this.readFeaturesFromNode(/** @type {Node} */ (source), opt_options);
+    if (!source) {
+      return [];
     } else if (typeof source === 'string') {
       const doc = parse(source);
       return this.readFeaturesFromDocument(doc, opt_options);
+    } else if (isDocument(source)) {
+      return this.readFeaturesFromDocument(
+        /** @type {Document} */ (source), opt_options);
     } else {
-      return [];
+      return this.readFeaturesFromNode(/** @type {Node} */ (source), opt_options);
     }
   }
 
@@ -128,16 +128,16 @@ class XMLFeature extends FeatureFormat {
    * @inheritDoc
    */
   readGeometry(source, opt_options) {
-    if (isDocument(source)) {
-      return this.readGeometryFromDocument(
-        /** @type {Document} */ (source), opt_options);
-    } else if (isNode(source)) {
-      return this.readGeometryFromNode(/** @type {Node} */ (source), opt_options);
+    if (!source) {
+      return null;
     } else if (typeof source === 'string') {
       const doc = parse(source);
       return this.readGeometryFromDocument(doc, opt_options);
+    } else if (isDocument(source)) {
+      return this.readGeometryFromDocument(
+        /** @type {Document} */ (source), opt_options);
     } else {
-      return null;
+      return this.readGeometryFromNode(/** @type {Node} */ (source), opt_options);
     }
   }
 
@@ -169,15 +169,15 @@ class XMLFeature extends FeatureFormat {
    * @api
    */
   readProjection(source) {
-    if (isDocument(source)) {
-      return this.readProjectionFromDocument(/** @type {Document} */ (source));
-    } else if (isNode(source)) {
-      return this.readProjectionFromNode(/** @type {Node} */ (source));
+    if (!source) {
+      return null;
     } else if (typeof source === 'string') {
       const doc = parse(source);
       return this.readProjectionFromDocument(doc);
+    } else if (isDocument(source)) {
+      return this.readProjectionFromDocument(/** @type {Document} */ (source));
     } else {
-      return null;
+      return this.readProjectionFromNode(/** @type {Node} */ (source));
     }
   }
 
diff --git a/src/ol/interaction/Draw.js b/src/ol/interaction/Draw.js
index 3cb00728e2..001c9259a2 100644
--- a/src/ol/interaction/Draw.js
+++ b/src/ol/interaction/Draw.js
@@ -56,7 +56,7 @@ import {createEditingStyle} from '../style/Style.js';
  * @property {import("../events/condition.js").Condition} [finishCondition] A function
  * that takes an {@link module:ol/MapBrowserEvent~MapBrowserEvent} and returns a
  * boolean to indicate whether the drawing can be finished.
- * @property {import("../style/Style.js").default|Array<import("../style/Style.js").default>|import("../style/Style.js").StyleFunction} [style]
+ * @property {import("../style/Style.js").StyleLike} [style]
  * Style for sketch features.
  * @property {GeometryFunction} [geometryFunction]
  * Function that is called when a geometry's coordinates are updated.
@@ -206,7 +206,7 @@ class Draw extends PointerInteraction {
     this.downPx_ = null;
 
     /**
-     * @type {any}
+     * @type {?}
      * @private
      */
     this.downTimeout_;
@@ -734,12 +734,12 @@ class Draw extends PointerInteraction {
     }
     /** @type {LineString} */
     let sketchLineGeom;
-    if (geometry instanceof Polygon &&
+    if (geometry.getType() == GeometryType.POLYGON &&
         this.mode_ !== Mode.POLYGON) {
       if (!this.sketchLine_) {
         this.sketchLine_ = new Feature();
       }
-      const ring = geometry.getLinearRing(0);
+      const ring = /** @type {Polygon} */ (geometry).getLinearRing(0);
       sketchLineGeom = /** @type {LineString} */ (this.sketchLine_.getGeometry());
       if (!sketchLineGeom) {
         sketchLineGeom = new LineString(ring.getFlatCoordinates(), ring.getLayout());
diff --git a/src/ol/interaction/Extent.js b/src/ol/interaction/Extent.js
index 58de76db9f..630ec46039 100644
--- a/src/ol/interaction/Extent.js
+++ b/src/ol/interaction/Extent.js
@@ -3,7 +3,6 @@
  */
 import Feature from '../Feature.js';
 import MapBrowserEventType from '../MapBrowserEventType.js';
-import MapBrowserPointerEvent from '../MapBrowserPointerEvent.js';
 import {squaredDistanceToSegment, closestOnSegment, distance as coordinateDistance, squaredDistance as squaredCoordinateDistance} from '../coordinate.js';
 import Event from '../events/Event.js';
 import {boundingExtent, getArea} from '../extent.js';
@@ -20,12 +19,12 @@ import {createEditingStyle} from '../style/Style.js';
  * @typedef {Object} Options
  * @property {import("../extent.js").Extent} [extent] Initial extent. Defaults to no
  * initial extent.
- * @property {import("../style/Style.js").default|Array<import("../style/Style.js").default>|import("../style/Style.js").StyleFunction} [boxStyle]
+ * @property {import("../style/Style.js").StyleLike} [boxStyle]
  * Style for the drawn extent box. Defaults to
  * {@link module:ol/style/Style~createEditing()['Polygon']}
  * @property {number} [pixelTolerance=10] Pixel tolerance for considering the
  * pointer close enough to a segment or vertex for editing.
- * @property {import("../style/Style.js").default|Array<import("../style/Style.js").default>|import("../style/Style.js").StyleFunction} [pointerStyle]
+ * @property {import("../style/Style.js").StyleLike} [pointerStyle]
  * Style for the cursor used to draw the extent. Defaults to
  * {@link module:ol/style/Style~createEditing()['Point']}
  * @property {boolean} [wrapX=false] Wrap the drawn extent across multiple maps
@@ -276,7 +275,7 @@ class ExtentInteraction extends PointerInteraction {
    * @inheritDoc
    */
   handleEvent(mapBrowserEvent) {
-    if (!(mapBrowserEvent instanceof MapBrowserPointerEvent)) {
+    if (!(/** @type {import("../MapBrowserPointerEvent.js").default} */ (mapBrowserEvent).pointerEvent)) {
       return true;
     }
     //display pointer (if not dragging)
diff --git a/src/ol/interaction/Modify.js b/src/ol/interaction/Modify.js
index 11842ec099..c4d6f05840 100644
--- a/src/ol/interaction/Modify.js
+++ b/src/ol/interaction/Modify.js
@@ -6,7 +6,6 @@ import Collection from '../Collection.js';
 import CollectionEventType from '../CollectionEventType.js';
 import Feature from '../Feature.js';
 import MapBrowserEventType from '../MapBrowserEventType.js';
-import MapBrowserPointerEvent from '../MapBrowserPointerEvent.js';
 import {equals} from '../array.js';
 import {equals as coordinatesEqual, distance as coordinateDistance, squaredDistance as squaredCoordinateDistance, squaredDistanceToSegment, closestOnSegment} from '../coordinate.js';
 import {listen, unlisten} from '../events.js';
@@ -87,7 +86,7 @@ const ModifyEventType = {
  * features. Default is {@link module:ol/events/condition~always}.
  * @property {number} [pixelTolerance=10] Pixel tolerance for considering the
  * pointer close enough to a segment or vertex for editing.
- * @property {import("../style/Style.js").default|Array<import("../style/Style.js").default>|import("../style/Style.js").StyleFunction} [style]
+ * @property {import("../style/Style.js").StyleLike} [style]
  * Style used for the features being modified. By default the default edit
  * style is used (see {@link module:ol/style}).
  * @property {VectorSource} [source] The vector source with
@@ -111,7 +110,7 @@ export class ModifyEvent extends Event {
    * @param {ModifyEventType} type Type.
    * @param {Collection<Feature>} features
    * The features modified.
-   * @param {MapBrowserPointerEvent} mapBrowserPointerEvent
+   * @param {import("../MapBrowserPointerEvent.js").default} mapBrowserPointerEvent
    * Associated {@link module:ol/MapBrowserPointerEvent}.
    */
   constructor(type, features, mapBrowserPointerEvent) {
@@ -324,7 +323,7 @@ class Modify extends PointerInteraction {
       this.handleFeatureRemove_, this);
 
     /**
-     * @type {MapBrowserPointerEvent}
+     * @type {import("../MapBrowserPointerEvent.js").default}
      * @private
      */
     this.lastPointerEvent_ = null;
@@ -349,7 +348,7 @@ class Modify extends PointerInteraction {
   }
 
   /**
-   * @param {MapBrowserPointerEvent} evt Map browser event
+   * @param {import("../MapBrowserPointerEvent.js").default} evt Map browser event
    * @private
    */
   willModifyFeatures_(evt) {
@@ -666,7 +665,7 @@ class Modify extends PointerInteraction {
    * @override
    */
   handleEvent(mapBrowserEvent) {
-    if (!(mapBrowserEvent instanceof MapBrowserPointerEvent)) {
+    if (!(/** @type {import("../MapBrowserPointerEvent.js").default} */ (mapBrowserEvent).pointerEvent)) {
       return true;
     }
     this.lastPointerEvent_ = mapBrowserEvent;
diff --git a/src/ol/interaction/MouseWheelZoom.js b/src/ol/interaction/MouseWheelZoom.js
index 1f9580b647..3d7c75d5a9 100644
--- a/src/ol/interaction/MouseWheelZoom.js
+++ b/src/ol/interaction/MouseWheelZoom.js
@@ -108,7 +108,7 @@ class MouseWheelZoom extends Interaction {
 
     /**
      * @private
-     * @type {any}
+     * @type {?}
      */
     this.timeoutId_;
 
@@ -126,7 +126,7 @@ class MouseWheelZoom extends Interaction {
     this.trackpadEventGap_ = 400;
 
     /**
-     * @type {any}
+     * @type {?}
      */
     this.trackpadTimeoutId_;
 
diff --git a/src/ol/interaction/Pointer.js b/src/ol/interaction/Pointer.js
index 964ec690c2..ecaf8df1d2 100644
--- a/src/ol/interaction/Pointer.js
+++ b/src/ol/interaction/Pointer.js
@@ -2,17 +2,16 @@
  * @module ol/interaction/Pointer
  */
 import MapBrowserEventType from '../MapBrowserEventType.js';
-import MapBrowserPointerEvent from '../MapBrowserPointerEvent.js';
 import Interaction from '../interaction/Interaction.js';
 import {getValues} from '../obj.js';
 
 
 /**
  * @typedef {Object} Options
- * @property {function(MapBrowserPointerEvent):boolean} [handleDownEvent]
+ * @property {function(import("../MapBrowserPointerEvent.js").default):boolean} [handleDownEvent]
  * Function handling "down" events. If the function returns `true` then a drag
  * sequence is started.
- * @property {function(MapBrowserPointerEvent)} [handleDragEvent]
+ * @property {function(import("../MapBrowserPointerEvent.js").default)} [handleDragEvent]
  * Function handling "drag" events. This function is called on "move" events
  * during a drag sequence.
  * @property {function(import("../MapBrowserEvent.js").default):boolean} [handleEvent]
@@ -20,11 +19,11 @@ import {getValues} from '../obj.js';
  * dispatched to the map. The function may return `false` to prevent the
  * propagation of the event to other interactions in the map's interactions
  * chain.
- * @property {function(MapBrowserPointerEvent)} [handleMoveEvent]
+ * @property {function(import("../MapBrowserPointerEvent.js").default)} [handleMoveEvent]
  * Function handling "move" events. This function is called on "move" events,
  * also during a drag sequence (so during a drag sequence both the
  * `handleDragEvent` function and this function are called).
- * @property {function(MapBrowserPointerEvent):boolean} [handleUpEvent]
+ * @property {function(import("../MapBrowserPointerEvent.js").default):boolean} [handleUpEvent]
  *  Function handling "up" events. If the function returns `false` then the
  * current drag sequence is stopped.
  * @property {function(boolean):boolean} [stopDown]
@@ -96,7 +95,7 @@ class PointerInteraction extends Interaction {
 
   /**
    * Handle pointer down events.
-   * @param {MapBrowserPointerEvent} mapBrowserEvent Event.
+   * @param {import("../MapBrowserPointerEvent.js").default} mapBrowserEvent Event.
    * @return {boolean} If the event was consumed.
    * @protected
    */
@@ -106,7 +105,7 @@ class PointerInteraction extends Interaction {
 
   /**
    * Handle pointer drag events.
-   * @param {MapBrowserPointerEvent} mapBrowserEvent Event.
+   * @param {import("../MapBrowserPointerEvent.js").default} mapBrowserEvent Event.
    * @protected
    */
   handleDragEvent(mapBrowserEvent) {}
@@ -119,7 +118,7 @@ class PointerInteraction extends Interaction {
    * @api
    */
   handleEvent(mapBrowserEvent) {
-    if (!(mapBrowserEvent instanceof MapBrowserPointerEvent)) {
+    if (!(/** @type {import("../MapBrowserPointerEvent.js").default} */ (mapBrowserEvent).pointerEvent)) {
       return true;
     }
 
@@ -149,14 +148,14 @@ class PointerInteraction extends Interaction {
 
   /**
    * Handle pointer move events.
-   * @param {MapBrowserPointerEvent} mapBrowserEvent Event.
+   * @param {import("../MapBrowserPointerEvent.js").default} mapBrowserEvent Event.
    * @protected
    */
   handleMoveEvent(mapBrowserEvent) {}
 
   /**
    * Handle pointer up events.
-   * @param {MapBrowserPointerEvent} mapBrowserEvent Event.
+   * @param {import("../MapBrowserPointerEvent.js").default} mapBrowserEvent Event.
    * @return {boolean} If the event was consumed.
    * @protected
    */
@@ -175,7 +174,7 @@ class PointerInteraction extends Interaction {
   }
 
   /**
-   * @param {MapBrowserPointerEvent} mapBrowserEvent Event.
+   * @param {import("../MapBrowserPointerEvent.js").default} mapBrowserEvent Event.
    * @private
    */
   updateTrackedPointers_(mapBrowserEvent) {
@@ -216,7 +215,7 @@ export function centroid(pointerEvents) {
 
 
 /**
- * @param {MapBrowserPointerEvent} mapBrowserEvent Event.
+ * @param {import("../MapBrowserPointerEvent.js").default} mapBrowserEvent Event.
  * @return {boolean} Whether the event is a pointerdown, pointerdrag
  *     or pointerup event.
  */
diff --git a/src/ol/interaction/Select.js b/src/ol/interaction/Select.js
index eafd63aa01..e713456eae 100644
--- a/src/ol/interaction/Select.js
+++ b/src/ol/interaction/Select.js
@@ -60,7 +60,7 @@ const SelectEventType = {
  * in the map and should return `true` for layers that you want to be
  * selectable. If the option is absent, all visible layers will be considered
  * selectable.
- * @property {import("../style/Style.js").default|Array<import("../style/Style.js").default>|import("../style/Style.js").StyleFunction} [style]
+ * @property {import("../style/Style.js").StyleLike} [style]
  * Style for the selected features. By default the default edit style is used
  * (see {@link module:ol/style}).
  * @property {import("../events/condition.js").Condition} [removeCondition] A function
diff --git a/src/ol/interaction/Snap.js b/src/ol/interaction/Snap.js
index 8f4aae7d35..66f3d2ef15 100644
--- a/src/ol/interaction/Snap.js
+++ b/src/ol/interaction/Snap.js
@@ -2,7 +2,6 @@
  * @module ol/interaction/Snap
  */
 import {getUid} from '../util.js';
-import {CollectionEvent} from '../Collection.js';
 import CollectionEventType from '../CollectionEventType.js';
 import {distance as coordinateDistance, squaredDistance as squaredCoordinateDistance, closestOnCircle, closestOnSegment, squaredDistanceToSegment} from '../coordinate.js';
 import {listen, unlistenByKey} from '../events.js';
@@ -13,7 +12,6 @@ import GeometryType from '../geom/GeometryType.js';
 import {fromCircle} from '../geom/Polygon.js';
 import PointerInteraction from '../interaction/Pointer.js';
 import {getValues} from '../obj.js';
-import {VectorSourceEvent} from '../source/Vector.js';
 import VectorEventType from '../source/VectorEventType.js';
 import RBush from '../structs/RBush.js';
 
@@ -44,6 +42,19 @@ import RBush from '../structs/RBush.js';
  */
 
 
+/**
+ * @param  {import("../source/Vector.js").VectorSourceEvent|import("../Collection.js").CollectionEvent} evt Event.
+ * @return {import("../Feature.js").default} Feature.
+ */
+function getFeatureFromEvent(evt) {
+  if (/** @type {import("../source/Vector.js").VectorSourceEvent} */ (evt).feature) {
+    return /** @type {import("../source/Vector.js").VectorSourceEvent} */ (evt).feature;
+  } else if (/** @type {import("../Collection.js").CollectionEvent} */ (evt).element) {
+    return /** @type {import("../Feature.js").default} */ (/** @type {import("../Collection.js").CollectionEvent} */ (evt).element);
+  }
+
+}
+
 /**
  * @classdesc
  * Handles snapping of vector features while modifying or drawing them.  The
@@ -259,12 +270,7 @@ class Snap extends PointerInteraction {
    * @private
    */
   handleFeatureAdd_(evt) {
-    let feature;
-    if (evt instanceof VectorSourceEvent) {
-      feature = evt.feature;
-    } else if (evt instanceof CollectionEvent) {
-      feature = /** @type {import("../Feature.js").default} */ (evt.element);
-    }
+    const feature = getFeatureFromEvent(evt);
     this.addFeature(feature);
   }
 
@@ -273,12 +279,7 @@ class Snap extends PointerInteraction {
    * @private
    */
   handleFeatureRemove_(evt) {
-    let feature;
-    if (evt instanceof VectorSourceEvent) {
-      feature = evt.feature;
-    } else if (evt instanceof CollectionEvent) {
-      feature = /** @type {import("../Feature.js").default} */ (evt.element);
-    }
+    const feature = getFeatureFromEvent(evt);
     this.removeFeature(feature);
   }
 
diff --git a/src/ol/layer/Group.js b/src/ol/layer/Group.js
index dad484f00a..d910f27b80 100644
--- a/src/ol/layer/Group.js
+++ b/src/ol/layer/Group.js
@@ -84,9 +84,8 @@ class LayerGroup extends BaseLayer {
       if (Array.isArray(layers)) {
         layers = new Collection(layers.slice(), {unique: true});
       } else {
-        assert(layers instanceof Collection,
+        assert(typeof /** @type {?} */ (layers).getArray === 'function',
           43); // Expected `layers` to be an array or a `Collection`
-        layers = layers;
       }
     } else {
       layers = new Collection(undefined, {unique: true});
diff --git a/src/ol/layer/Vector.js b/src/ol/layer/Vector.js
index fce5feff5a..b5a3eb7846 100644
--- a/src/ol/layer/Vector.js
+++ b/src/ol/layer/Vector.js
@@ -41,7 +41,7 @@ import {createDefaultStyle, toFunction as toStyleFunction} from '../style/Style.
  * @property {boolean} [declutter=false] Declutter images and text. Decluttering is applied to all
  * image and text styles, and the priority is defined by the z-index of the style. Lower z-index
  * means higher priority.
- * @property {import("../style/Style.js").default|Array<import("../style/Style.js").default>|import("../style/Style.js").StyleFunction} [style] Layer style. See
+ * @property {import("../style/Style.js").StyleLike} [style] Layer style. See
  * {@link module:ol/style} for default style which will be used if this is not defined.
  * @property {boolean} [updateWhileAnimating=false] When set to `true` and `renderMode`
  * is `vector`, feature batches will be recreated during animations. This means that no
@@ -119,7 +119,7 @@ class VectorLayer extends Layer {
 
     /**
     * User provided style.
-    * @type {import("../style/Style.js").default|Array<import("../style/Style.js").default>|import("../style/Style.js").StyleFunction}
+    * @type {import("../style/Style.js").StyleLike}
     * @private
     */
     this.style_ = null;
@@ -196,7 +196,7 @@ class VectorLayer extends Layer {
   /**
   * Get the style for features.  This returns whatever was passed to the `style`
   * option at construction or to the `setStyle` method.
-  * @return {import("../style/Style.js").default|Array<import("../style/Style.js").default>|import("../style/Style.js").StyleFunction}
+  * @return {import("../style/Style.js").StyleLike}
   *     Layer style.
   * @api
   */
diff --git a/src/ol/layer/VectorTile.js b/src/ol/layer/VectorTile.js
index df8c39d4ab..83bc354791 100644
--- a/src/ol/layer/VectorTile.js
+++ b/src/ol/layer/VectorTile.js
@@ -70,7 +70,7 @@ export const RenderType = {
  * image and text styles, and the priority is defined by the z-index of the style. Lower z-index
  * means higher priority. When set to `true`, a `renderMode` of `'image'` will be overridden with
  * `'hybrid'`.
- * @property {import("../style/Style.js").default|Array<import("../style/Style.js").default>|import("../style/Style.js").StyleFunction} [style] Layer style. See
+ * @property {import("../style/Style.js").StyleLike} [style] Layer style. See
  * {@link module:ol/style} for default style which will be used if this is not defined.
  * @property {boolean} [updateWhileAnimating=false] When set to `true`, feature batches will be
  * recreated during animations. This means that no vectors will be shown clipped, but the setting
@@ -82,7 +82,7 @@ export const RenderType = {
  * means no preloading.
  * @property {import("../render.js").OrderFunction} [renderOrder] Render order. Function to be used when sorting
  * features before rendering. By default features are drawn in the order that they are created.
- * @property {import("../style/Style.js").default|Array<import("../style/Style.js").default>|import("../style/Style.js").StyleFunction} [style] Layer style. See
+ * @property {import("../style/Style.js").StyleLike} [style] Layer style. See
  * {@link module:ol/style} for default style which will be used if this is not defined.
  * @property {boolean} [useInterimTilesOnError=true] Use interim tiles on error.
  */
diff --git a/src/ol/pointer/TouchSource.js b/src/ol/pointer/TouchSource.js
index 316a4233ae..332bd051aa 100644
--- a/src/ol/pointer/TouchSource.js
+++ b/src/ol/pointer/TouchSource.js
@@ -137,7 +137,7 @@ class TouchSource extends EventSource {
 
     /**
      * @private
-     * @type {any}
+     * @type {?}
      */
     this.resetId_;
 
diff --git a/src/ol/source/Cluster.js b/src/ol/source/Cluster.js
index 3754df9f36..74649500e4 100644
--- a/src/ol/source/Cluster.js
+++ b/src/ol/source/Cluster.js
@@ -5,6 +5,7 @@
 import {getUid} from '../util.js';
 import {assert} from '../asserts.js';
 import Feature from '../Feature.js';
+import GeometryType from '../geom/GeometryType.js';
 import {scale as scaleCoordinate, add as addCoordinate} from '../coordinate.js';
 import {listen} from '../events.js';
 import EventType from '../events/EventType.js';
@@ -76,7 +77,7 @@ class Cluster extends VectorSource {
      */
     this.geometryFunction = options.geometryFunction || function(feature) {
       const geometry = /** @type {Point} */ (feature.getGeometry());
-      assert(geometry instanceof Point,
+      assert(geometry.getType() == GeometryType.POINT,
         10); // The default `geometryFunction` can only handle `Point` geometries
       return geometry;
     };
diff --git a/src/ol/source/Image.js b/src/ol/source/Image.js
index e8a643ddc0..2c83fd0d3c 100644
--- a/src/ol/source/Image.js
+++ b/src/ol/source/Image.js
@@ -230,10 +230,7 @@ class ImageSource extends Source {
  * @param {string} src Source.
  */
 export function defaultImageLoadFunction(image, src) {
-  const img = image.getImage();
-  if (img instanceof HTMLImageElement || img instanceof HTMLVideoElement) {
-    img.src = src;
-  }
+  /** @type {HTMLImageElement|HTMLVideoElement} */ (image.getImage()).src = src;
 }
 
 
diff --git a/src/ol/source/Raster.js b/src/ol/source/Raster.js
index 1bd7d4d1d7..7147f35870 100644
--- a/src/ol/source/Raster.js
+++ b/src/ol/source/Raster.js
@@ -11,7 +11,6 @@ import EventType from '../events/EventType.js';
 import {Processor} from 'pixelworks/lib/index';
 import {equals, getCenter, getHeight, getWidth} from '../extent.js';
 import LayerType from '../LayerType.js';
-import Layer from '../layer/Layer.js';
 import ImageLayer from '../layer/Image.js';
 import TileLayer from '../layer/Tile.js';
 import {assign} from '../obj.js';
@@ -19,7 +18,6 @@ import CanvasImageLayerRenderer from '../renderer/canvas/ImageLayer.js';
 import CanvasTileLayerRenderer from '../renderer/canvas/TileLayer.js';
 import ImageSource from '../source/Image.js';
 import SourceState from '../source/State.js';
-import TileSource from '../source/Tile.js';
 import {create as createTransform} from '../transform.js';
 
 
@@ -488,20 +486,22 @@ function createRenderers(sources) {
 
 /**
  * Create a renderer for the provided source.
- * @param {import("./Source.js").default|import("../layer/Layer.js").default} source The source.
+ * @param {import("./Source.js").default|import("../layer/Layer.js").default} layerOrSource The layer or source.
  * @return {import("../renderer/canvas/Layer.js").default} The renderer.
  */
-function createRenderer(source) {
+function createRenderer(layerOrSource) {
+  const tileSource = /** @type {import("./Tile.js").default} */ (layerOrSource);
+  const imageSource = /** @type {import("./Image.js").default} */ (layerOrSource);
+  const layer = /** @type {import("../layer/Layer.js").default} */ (layerOrSource);
   let renderer = null;
-  if (source instanceof TileSource) {
-    renderer = createTileRenderer(source);
-  } else if (source instanceof ImageSource) {
-    renderer = createImageRenderer(source);
-  } else if (source instanceof TileLayer) {
-    renderer = new CanvasTileLayerRenderer(source);
-  } else if (source instanceof Layer &&
-      (source.getType() == LayerType.IMAGE || source.getType() == LayerType.VECTOR)) {
-    renderer = new CanvasImageLayerRenderer(source);
+  if (typeof tileSource.getTile === 'function') {
+    renderer = createTileRenderer(tileSource);
+  } else if (typeof imageSource.getImage === 'function') {
+    renderer = createImageRenderer(imageSource);
+  } else if (layer.getType() === LayerType.TILE) {
+    renderer = new CanvasTileLayerRenderer(/** @type {import("../layer/Tile.js").default} */ (layer));
+  } else if (layer.getType() == LayerType.IMAGE || layer.getType() == LayerType.VECTOR) {
+    renderer = new CanvasImageLayerRenderer(/** @type {import("../layer/Image.js").default} */ (layer));
   }
   return renderer;
 }
diff --git a/src/ol/source/TileImage.js b/src/ol/source/TileImage.js
index dc4149f58d..cda8f3b368 100644
--- a/src/ol/source/TileImage.js
+++ b/src/ol/source/TileImage.js
@@ -392,10 +392,7 @@ class TileImage extends UrlTile {
  * @param {string} src Source.
  */
 function defaultTileLoadFunction(imageTile, src) {
-  const image = imageTile.getImage();
-  if (image instanceof HTMLImageElement || image instanceof HTMLVideoElement) {
-    image.src = src;
-  }
+  /** @type {HTMLImageElement|HTMLVideoElement} */ (imageTile.getImage()).src = src;
 }
 
 export default TileImage;
diff --git a/src/ol/source/Vector.js b/src/ol/source/Vector.js
index 4e1fce6f8f..0ec3573092 100644
--- a/src/ol/source/Vector.js
+++ b/src/ol/source/Vector.js
@@ -258,11 +258,11 @@ class VectorSource extends Source {
     this.featuresCollection_ = null;
 
     let collection, features;
-    if (options.features instanceof Collection) {
+    if (Array.isArray(options.features)) {
+      features = options.features;
+    } else if (options.features) {
       collection = options.features;
       features = collection.getArray();
-    } else if (Array.isArray(options.features)) {
-      features = options.features;
     }
     if (!useSpatialIndex && collection === undefined) {
       collection = new Collection(features);
diff --git a/src/ol/style/Fill.js b/src/ol/style/Fill.js
index 116f1b997b..8381c35910 100644
--- a/src/ol/style/Fill.js
+++ b/src/ol/style/Fill.js
@@ -76,13 +76,15 @@ class Fill {
    */
   getChecksum() {
     if (this.checksum_ === undefined) {
-      if (
-        this.color_ instanceof CanvasPattern ||
-          this.color_ instanceof CanvasGradient
-      ) {
-        this.checksum_ = getUid(this.color_).toString();
+      const color = this.color_;
+      if (color) {
+        if (Array.isArray(color) || typeof color == 'string') {
+          this.checksum_ = 'f' + asString(/** @type {import("../Color.js").Color|string} */ (color));
+        } else {
+          this.checksum_ = getUid(this.color_).toString();
+        }
       } else {
-        this.checksum_ = 'f' + (this.color_ ? asString(this.color_) : '-');
+        this.checksum_ = 'f-';
       }
     }
 
diff --git a/src/ol/style/Icon.js b/src/ol/style/Icon.js
index 9ca81686a4..b5201313c2 100644
--- a/src/ol/style/Icon.js
+++ b/src/ol/style/Icon.js
@@ -149,7 +149,7 @@ class Icon extends ImageStyle {
       5); // `imgSize` must be set when `image` is provided
 
     if ((src === undefined || src.length === 0) && image) {
-      src = image instanceof HTMLImageElement && image.src || getUid(image).toString();
+      src = /** @type {HTMLImageElement} */ (image).src || getUid(image).toString();
     }
     assert(src !== undefined && src.length > 0,
       6); // A defined and non-empty `src` or `image` must be provided
diff --git a/src/ol/style/IconImage.js b/src/ol/style/IconImage.js
index e85106bcb8..d94cbec242 100644
--- a/src/ol/style/IconImage.js
+++ b/src/ol/style/IconImage.js
@@ -34,8 +34,8 @@ class IconImage extends EventTarget {
      */
     this.image_ = !image ? new Image() : image;
 
-    if (crossOrigin !== null && this.image_ instanceof HTMLImageElement) {
-      this.image_.crossOrigin = crossOrigin;
+    if (crossOrigin !== null) {
+      /** @type {HTMLImageElement} */ (this.image_).crossOrigin = crossOrigin;
     }
 
     /**
diff --git a/src/ol/style/Style.js b/src/ol/style/Style.js
index 36ba389ab4..2bf94e4b61 100644
--- a/src/ol/style/Style.js
+++ b/src/ol/style/Style.js
@@ -87,7 +87,6 @@
  * ```
  */
 import {assert} from '../asserts.js';
-import Geometry from '../geom/Geometry.js';
 import GeometryType from '../geom/GeometryType.js';
 import CircleStyle from '../style/Circle.js';
 import Fill from '../style/Fill.js';
@@ -103,6 +102,10 @@ import Stroke from '../style/Stroke.js';
  * @typedef {function(import("../Feature.js").FeatureLike, number):(Style|Array<Style>)} StyleFunction
  */
 
+/**
+ * A {@link Style}, an array of {@link Style}, or a {@link StyleFunction}.
+ * @typedef {Style|Array<Style>|StyleFunction} StyleLike
+ */
 
 /**
  * A function that takes an {@link module:ol/Feature} as argument and returns an
@@ -137,7 +140,6 @@ import Stroke from '../style/Stroke.js';
  * @property {number} [zIndex] Z index.
  */
 
-
 /**
  * @classdesc
  * Container for vector feature rendering styles. Any changes made to the style
@@ -214,8 +216,8 @@ class Style {
    */
   clone() {
     let geometry = this.getGeometry();
-    if (geometry instanceof Geometry) {
-      geometry = geometry.clone();
+    if (geometry && typeof geometry === 'object') {
+      geometry = /** @type {import("../geom/Geometry.js").default} */ (geometry).clone();
     }
     return new Style({
       geometry: geometry,
@@ -411,9 +413,10 @@ export function toFunction(obj) {
     if (Array.isArray(obj)) {
       styles = obj;
     } else {
-      assert(obj instanceof Style,
+      assert(typeof /** @type {?} */ (obj).getZIndex === 'function',
         41); // Expected an `Style` or an array of `Style`
-      styles = [obj];
+      const style = /** @type {Style} */ (obj);
+      styles = [style];
     }
     styleFunction = function() {
       return styles;
diff --git a/src/ol/xml.js b/src/ol/xml.js
index 69ce83e384..8c262f9bc7 100644
--- a/src/ol/xml.js
+++ b/src/ol/xml.js
@@ -89,20 +89,11 @@ export function getAllTextContent_(node, normalizeWhitespace, accumulator) {
 
 
 /**
- * @param {?} value Value.
- * @return {boolean} Is document.
+ * @param {Object} object Object.
+ * @return {boolean} Is a document.
  */
-export function isDocument(value) {
-  return value instanceof Document;
-}
-
-
-/**
- * @param {?} value Value.
- * @return {boolean} Is node.
- */
-export function isNode(value) {
-  return value instanceof Node;
+export function isDocument(object) {
+  return 'documentElement' in object;
 }