diff --git a/src/ol/control/OverviewMap.js b/src/ol/control/OverviewMap.js
index 93fceff482..020a49d9f2 100644
--- a/src/ol/control/OverviewMap.js
+++ b/src/ol/control/OverviewMap.js
@@ -51,8 +51,8 @@ class ControlledMap extends PluggableMap {
  * @property {boolean} [collapsible=true] Whether the control can be collapsed or not.
  * @property {string|HTMLElement} [label='»'] Text label to use for the collapsed
  * overviewmap button. Instead of text, also an element (e.g. a `span` element) can be used.
- * @property {Array<import("../layer/Layer.js").default>|import("../Collection.js").default<import("../layer/Layer.js").default>} layers
- * Layers for the overview map (mandatory).
+ * @property {Array<import("../layer/Layer.js").default>|import("../Collection.js").default<import("../layer/Layer.js").default>} [layers]
+ * Layers for the overview map.
  * @property {function(import("../MapEvent.js").default)} [render] Function called when the control
  * should be re-rendered. This is called in a `requestAnimationFrame` callback.
  * @property {HTMLElement|string} [target] Specify a target if you want the control
@@ -76,7 +76,7 @@ class OverviewMap extends Control {
    */
   constructor(opt_options) {
 
-    const options = opt_options ? opt_options : /** @type {Options} */ ({});
+    const options = opt_options ? opt_options : {};
 
     super({
       element: document.createElement('div'),