📝 Provide detailed reproduction steps (if any)

There is no easy way to reproduce the issue without a React application. Due to its nature and double rendering in StrictMode, the editor might try to operate on a DOM element that is no longer available.

L319, domRoot might be undefined when a DOM element is no longer available.

When the application crashes, it shows the following trace:

TypeError: Cannot read properties of undefined (reading 'attributes')
    at Zc.detachDomRoot (VM3382 ckeditor5.js:5:161689)
    at wC.destroy (VM3382 ckeditor5.js:5:768794)
    at vC.destroy (VM3382 ckeditor5.js:5:771313)

✔️ Expected result

No error. The application should not crash.

❌ Actual result

As reported above.

📃 Other details

• Related PR: React 19 support ckeditor5-react#480.
• The following diff resolves all my issues.

   diff --git a/packages/ckeditor5-engine/src/view/view.ts b/packages/ckeditor5-engine/src/view/view.ts
   index 6c1e533122..11477e433e 100644
   --- a/packages/ckeditor5-engine/src/view/view.ts
   +++ b/packages/ckeditor5-engine/src/view/view.ts
   @@ -316,7 +316,11 @@ export default class View extends /* #__PURE__ */ ObservableMixin() {
            * @param name Name of the root to detach.
            */
           public detachDomRoot( name: string ): void {
   -               const domRoot = this.domRoots.get( name )!;
   +               const domRoot = this.domRoots.get( name );
   +
   +               if ( !domRoot ) {
   +                       return;
   +               }
   
                   // Remove all root attributes so the DOM element is "bare".
                   Array.from( domRoot.attributes ).forEach( ( { name } ) => domRoot.removeAttribute( name ) );
  

• This is not the first time that suppressing TypeSccript possible null values results in unexpected errors in the applications consuming the editor.