diff --git a/src/ol/MapBrowserEventHandler.js b/src/ol/MapBrowserEventHandler.js
index dd950f0488..4254838045 100644
--- a/src/ol/MapBrowserEventHandler.js
+++ b/src/ol/MapBrowserEventHandler.js
@@ -140,6 +140,7 @@ class MapBrowserEventHandler extends EventTarget {
     } else {
       // click
       this.clickTimeoutId_ = setTimeout(
+        /** @this {MapBrowserEventHandler} */
         function () {
           this.clickTimeoutId_ = undefined;
           const newEvent = new MapBrowserEvent(
diff --git a/src/ol/PluggableMap.js b/src/ol/PluggableMap.js
index d02777b09a..26ec858de6 100644
--- a/src/ol/PluggableMap.js
+++ b/src/ol/PluggableMap.js
@@ -187,7 +187,7 @@ class PluggableMap extends BaseObject {
     /**
      * @private
      */
-    this.animationDelay_ = function () {
+    this.animationDelay_ = /** @this {PluggableMap} */ function () {
       this.animationDelayKey_ = undefined;
       this.renderFrame_(Date.now());
     }.bind(this);
diff --git a/src/ol/interaction/Draw.js b/src/ol/interaction/Draw.js
index dd6281a343..dc861c4131 100644
--- a/src/ol/interaction/Draw.js
+++ b/src/ol/interaction/Draw.js
@@ -109,8 +109,8 @@ import {squaredDistance as squaredCoordinateDistance} from '../coordinate.js';
  * and a projection as arguments, and returns a geometry. The optional existing
  * geometry is the geometry that is returned when the function is called without
  * a second argument.
- * @typedef {function(!SketchCoordType, import("../geom/SimpleGeometry.js").default=,
- *     import("../proj/Projection.js").default=):
+ * @typedef {function(!SketchCoordType, import("../geom/SimpleGeometry.js").default,
+ *     import("../proj/Projection.js").default):
  *     import("../geom/SimpleGeometry.js").default} GeometryFunction
  */
 
@@ -299,13 +299,13 @@ class Draw extends PointerInteraction {
       if (this.type_ === GeometryType.CIRCLE) {
         /**
          * @param {!LineCoordType} coordinates The coordinates.
-         * @param {import("../geom/SimpleGeometry.js").default=} opt_geometry Optional geometry.
+         * @param {import("../geom/SimpleGeometry.js").default|undefined} geometry Optional geometry.
          * @param {import("../proj/Projection.js").default} projection The view projection.
          * @return {import("../geom/SimpleGeometry.js").default} A geometry.
          */
-        geometryFunction = function (coordinates, opt_geometry, projection) {
-          const circle = opt_geometry
-            ? /** @type {Circle} */ (opt_geometry)
+        geometryFunction = function (coordinates, geometry, projection) {
+          const circle = geometry
+            ? /** @type {Circle} */ (geometry)
             : new Circle([NaN, NaN]);
           const center = fromUserCoordinate(coordinates[0], projection);
           const squaredLength = squaredCoordinateDistance(
@@ -331,12 +331,11 @@ class Draw extends PointerInteraction {
         }
         /**
          * @param {!LineCoordType} coordinates The coordinates.
-         * @param {import("../geom/SimpleGeometry.js").default=} opt_geometry Optional geometry.
+         * @param {import("../geom/SimpleGeometry.js").default|undefined} geometry Optional geometry.
          * @param {import("../proj/Projection.js").default} projection The view projection.
          * @return {import("../geom/SimpleGeometry.js").default} A geometry.
          */
-        geometryFunction = function (coordinates, opt_geometry, projection) {
-          let geometry = opt_geometry;
+        geometryFunction = function (coordinates, geometry, projection) {
           if (geometry) {
             if (mode === Mode.POLYGON) {
               if (coordinates[0].length) {
diff --git a/src/ol/renderer/canvas/VectorLayer.js b/src/ol/renderer/canvas/VectorLayer.js
index 96c7ab4deb..872a9e513a 100644
--- a/src/ol/renderer/canvas/VectorLayer.js
+++ b/src/ol/renderer/canvas/VectorLayer.js
@@ -338,7 +338,11 @@ class CanvasVectorLayerRenderer extends CanvasLayerRenderer {
    */
   getFeatures(pixel) {
     return new Promise(
-      function (resolve, reject) {
+      /**
+       * @param {function(Array<import("../../Feature").default|import("../../render/Feature").default>): void} resolve Resolver function.
+       * @this {CanvasVectorLayerRenderer}
+       */
+      function (resolve) {
         if (!this.hitDetectionImageData_ && !this.animatingOrInteracting_) {
           const size = [this.context.canvas.width, this.context.canvas.height];
           apply(this.pixelTransform, size);
@@ -622,28 +626,29 @@ class CanvasVectorLayerRenderer extends CanvasLayerRenderer {
 
     const squaredTolerance = getSquaredRenderTolerance(resolution, pixelRatio);
 
-    /**
-     * @param {import("../../Feature.js").default} feature Feature.
-     * @this {CanvasVectorLayerRenderer}
-     */
-    const render = function (feature) {
-      let styles;
-      const styleFunction =
-        feature.getStyleFunction() || vectorLayer.getStyleFunction();
-      if (styleFunction) {
-        styles = styleFunction(feature, resolution);
-      }
-      if (styles) {
-        const dirty = this.renderFeature(
-          feature,
-          squaredTolerance,
-          styles,
-          replayGroup,
-          userTransform
-        );
-        this.dirty_ = this.dirty_ || dirty;
-      }
-    }.bind(this);
+    const render =
+      /**
+       * @param {import("../../Feature.js").default} feature Feature.
+       * @this {CanvasVectorLayerRenderer}
+       */
+      function (feature) {
+        let styles;
+        const styleFunction =
+          feature.getStyleFunction() || vectorLayer.getStyleFunction();
+        if (styleFunction) {
+          styles = styleFunction(feature, resolution);
+        }
+        if (styles) {
+          const dirty = this.renderFeature(
+            feature,
+            squaredTolerance,
+            styles,
+            replayGroup,
+            userTransform
+          );
+          this.dirty_ = this.dirty_ || dirty;
+        }
+      }.bind(this);
 
     const userExtent = toUserExtent(extent, projection);
     /** @type {Array<import("../../Feature.js").default>} */
diff --git a/src/ol/renderer/webgl/PointsLayer.js b/src/ol/renderer/webgl/PointsLayer.js
index da3d9dcb11..a756fbb02e 100644
--- a/src/ol/renderer/webgl/PointsLayer.js
+++ b/src/ol/renderer/webgl/PointsLayer.js
@@ -267,6 +267,10 @@ class WebGLPointsLayerRenderer extends WebGLLayerRenderer {
     this.worker_ = createWebGLWorker();
     this.worker_.addEventListener(
       'message',
+      /**
+       * @param {*} event Event.
+       * @this {WebGLPointsLayerRenderer}
+       */
       function (event) {
         const received = event.data;
         if (received.type === WebGLWorkerMessageType.GENERATE_BUFFERS) {
diff --git a/src/ol/resolutionconstraint.js b/src/ol/resolutionconstraint.js
index 0df73d9671..461c0b1f1f 100644
--- a/src/ol/resolutionconstraint.js
+++ b/src/ol/resolutionconstraint.js
@@ -13,7 +13,7 @@ import {linearFindNearest} from './array.js';
  * Returns a modified resolution taking into account the viewport size and maximum
  * allowed extent.
  * @param {number} resolution Resolution
- * @param {import("./extent.js").Extent=} maxExtent Maximum allowed extent.
+ * @param {import("./extent.js").Extent} maxExtent Maximum allowed extent.
  * @param {import("./size.js").Size} viewportSize Viewport size.
  * @param {boolean} showFullExtent Whether to show the full extent.
  * @return {number} Capped resolution.