use function overloading for better types

src/compat/eme/eme-api-implementation.ts

@@ -20,7 +20,10 @@ import getMozMediaKeysCallbacks, {
 import getOldKitWebKitMediaKeyCallbacks, {
   isOldWebkitMediaElement,
 } from "./custom_media_keys/old_webkit_media_keys";
-import type { ICustomMediaKeys } from "./custom_media_keys/types";
+import type {
+  ICustomMediaEncryptedEvent,
+  ICustomMediaKeys,
+} from "./custom_media_keys/types";
 import getWebKitMediaKeysCallbacks from "./custom_media_keys/webkit_media_keys";
 import { WebKitMediaKeysConstructor } from "./custom_media_keys/webkit_media_keys_constructor";
 
@@ -64,7 +67,7 @@ export interface IEmeApiImplementation {
    */
   onEncrypted: (
     target: IEventTargetLike,
-    listener: (evt: unknown) => void,
+    listener: (evt: ICustomMediaEncryptedEvent) => void,
     cancelSignal: CancellationSignal,
   ) => void;
 
@@ -286,7 +289,7 @@ function createOnEncryptedForWebkit(): IEmeApiImplementation["onEncrypted"] {
   );
   const onEncrypted = (
     target: IEventTargetLike,
-    listener: (event?: Event) => void,
+    listener: (event: ICustomMediaEncryptedEvent) => void,
     cancelSignal: CancellationSignal,
   ) => {
     compatibleEventListener(

src/compat/event_listeners.ts

@@ -29,6 +29,7 @@ import type {
   ICompatHTMLMediaElement,
   ICompatPictureInPictureWindow,
 } from "./browser_compatibility_types";
+import type { ICustomMediaEncryptedEvent } from "./eme/custom_media_keys/types";
 
 const BROWSER_PREFIXES = ["", "webkit", "moz", "ms"];
 
@@ -104,13 +105,32 @@ export type IEventTargetLike = HTMLElement | IEventEmitterLike | IEventEmitter<u
  * @returns {Function} - Returns function allowing to easily add a callback to
  * be triggered when that event is emitted on a given event target.
  */
+
+function createCompatibleEventListener(
+  eventNames: Array<"needkey" | "encrypted">,
+  prefixes?: string[],
+): (
+  element: IEventTargetLike,
+  listener: (event: ICustomMediaEncryptedEvent) => void,
+  cancelSignal: CancellationSignal,
+) => void;
+
 function createCompatibleEventListener(
   eventNames: string[],
   prefixes?: string[],
 ): (
   element: IEventTargetLike,
   listener: (event?: Event) => void,
   cancelSignal: CancellationSignal,
+) => void;
+
+function createCompatibleEventListener(
+  eventNames: string[] | Array<"needkey" | "encrypted">,
+  prefixes?: string[],
+): (
+  element: IEventTargetLike,
+  listener: (event?: Event | MediaEncryptedEvent) => void,
+  cancelSignal: CancellationSignal,
 ) => void {
   let mem: string | undefined;
   const prefixedEvents = eventPrefixed(eventNames, prefixes);

src/main_thread/decrypt/content_decryptor.ts

@@ -16,7 +16,6 @@
 
 import type { ICustomMediaKeys, ICustomMediaKeySystemAccess } from "../../compat/eme";
 import eme, { getInitData } from "../../compat/eme";
-import type { ICustomMediaEncryptedEvent } from "../../compat/eme/custom_media_keys/types";
 import config from "../../config";
 import { EncryptedMediaError, OtherError } from "../../errors";
 import log from "../../log";
@@ -169,7 +168,7 @@ export default class ContentDecryptor extends EventEmitter<IContentDecryptorEven
       mediaElement,
       (evt) => {
         log.debug("DRM: Encrypted event received from media element.");
-        const initData = getInitData(evt as ICustomMediaEncryptedEvent);
+        const initData = getInitData(evt);
         if (initData !== null) {
           this.onInitializationData(initData);
         }