Fix nullable types

src/plugins/syncPlay/core/Manager.js

@@ -246,7 +246,7 @@ class Manager {
 
     /**
      * Handles a playback command from the server.
-     * @param {Object} cmd The playback command.
+     * @param {Object|null} cmd The playback command.
      */
     processCommand(cmd) {
         if (cmd === null) return;
@@ -294,7 +294,7 @@ class Manager {
 
     /**
      * Handles a group state change.
-     * @param {Object} update The group state update.
+     * @param {Object|null} update The group state update.
      */
     processStateChange(update) {
         if (update === null || update.State === null || update.Reason === null) return;

src/scripts/dom.js

@@ -65,7 +65,7 @@ function containsAnyClass(classList, classNames) {
      * Returns parent of element with one of specified class names.
      * @param {HTMLElement} elem - Element whose parent need to find.
      * @param {(string|Array)} classNames - Class name or array of class names.
-     * @returns {HTMLElement} Parent with one of specified class names.
+     * @returns {HTMLElement|null} Parent with one of specified class names.
      */
 export function parentWithClass(elem, classNames) {
     // accept both string and array passed in