Revert "Merge pull request #12416 from ahocevar/eventtype-generics"

This reverts commit b6c143deb2, reversing
changes made to 7777821df5.

src/ol/Observable.js

@@ -5,11 +5,6 @@ import EventTarget from './events/Target.js';
 import EventType from './events/EventType.js';
 import {listen, listenOnce, unlistenByKey} from './events.js';
 
-/**
- * @template ChildTypes
- * @typedef {ChildTypes|'change'|'error'|Array<ChildTypes|'change'|'error'>} EventTypes
- */
-
 /**
  * @classdesc
  * Abstract base class; normally only used for creating subclasses and not
@@ -19,7 +14,6 @@ import {listen, listenOnce, unlistenByKey} from './events.js';
  * {@link module:ol/Observable~Observable#changed}.
  *
  * @fires import("./events/Event.js").default
- * @template {string} ChildTypes
  * @api
  */
 class Observable extends EventTarget {
@@ -54,7 +48,7 @@ class Observable extends EventTarget {
 
   /**
    * Listen for a certain type of event.
-   * @param {EventTypes<ChildTypes>} type The event type or array of event types.
+   * @param {string|Array<string>} type The event type or array of event types.
    * @param {function(?): ?} listener The listener function.
    * @return {import("./events.js").EventsKey|Array<import("./events.js").EventsKey>} Unique key for the listener. If
    *     called with an array of event types as the first argument, the return
@@ -76,7 +70,7 @@ class Observable extends EventTarget {
 
   /**
    * Listen once for a certain type of event.
-   * @param {EventTypes<ChildTypes>} type The event type or array of event types.
+   * @param {string|Array<string>} type The event type or array of event types.
    * @param {function(?): ?} listener The listener function.
    * @return {import("./events.js").EventsKey|Array<import("./events.js").EventsKey>} Unique key for the listener. If
    *     called with an array of event types as the first argument, the return
@@ -100,7 +94,7 @@ class Observable extends EventTarget {
 
   /**
    * Unlisten for a certain type of event.
-   * @param {EventTypes<ChildTypes>} type The event type or array of event types.
+   * @param {string|Array<string>} type The event type or array of event types.
    * @param {function(?): ?} listener The listener function.
    * @api
    */