[lexical] Feature: LexicalEditor RootListener and EditableListener can return unregister callbacks

[etrepum]

Description

LexicalEditor.registerRootListener and registerEditableListener can now optionally return an unregister callback that is called before each consecutive change and on unregister.

It's a common pattern to set up additional services that are only available based on the editor state, for example when it is attached to the DOM you may want to set up listeners on the root element or its containing document or window. It should also be easy to correctly clean up those listeners. The current pattern is something like this:

const listener = () => {};
let unregister = () => {};
return mergeRegister(
  editor.registerRootListener((nextRoot) => {
    unregister();
    unregister = () => {};
    if (nextRoot) {
      nextRoot.addEventListener('click', listener);
      unregister = () => nextRoot.removeEventListener('click', listener);
    }
  }),
  () => unregister(),
);

If the root listener is permitted to return an optional unregister directly, this becomes much less convoluted:

const listener = () => {};
return editor.registerRootListener((nextRoot) => {
  if (nextRoot) {
    nextRoot.addEventListener('click', listener);
    return () => nextRoot.removeEventListener('click', listener);
  }
});

The inspiration from this comes from how effect() works with preact signals

If the callback returns a function, this function will be run before the next value update.

Test plan

New unit tests, all existing unit and e2e tests pass with no change.

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
lexical	Ready	Preview, Comment	Mar 13, 2026 9:16pm
lexical-playground	Ready	Preview, Comment	Mar 13, 2026 9:16pm