TypeError: Cannot read properties of undefined (reading 'toLowerCase') in keyboard handler

Hi @artf, After digging deeper into the full stack trace, I found that the error is not in GrapesJS. The event.key.toLowerCase() call is coming from our own application code — a global window.addEventListener("keydown", ...) handler that we have elsewhere in our codebase, which runs alongside GrapesJS. Since our webpack build bundles multiple modules into the same chunk (dist/1348), The Sentry frame was misleading, and we incorrectly attributed the source to GrapesJS.

GrapesJS's own keyboard handling uses event.keyCode and is not involved in this error. This is entirely on our side, and we have a fix in place.

Regarding the jsfiddle, it was a genuine attempt to isolate the issue, not AI-generated. It simply wasn't set up correctly to reproduce the actual scenario. Closing this from our side, and apologies for the noise.

Hey @saeedhbi, where exactly do you see event.key.toLowerCase() in our code? Are you sure is not coming from your side? Unfortunately, the jsfiddle is not helpful, seems too much AI slopped 😅, it's not even loading the editor.

Maybe you can share the full stack trace to see where exactly this happening?

Thanks for reporting this, @saeedhbi.

Great question about TypeError: Cannot read properties of undefined (reading 'toLowerCase') in keyboard handler. The recommended approach with Canvas is to use the event-driven API.

Start here:

1. Check the GrapesJS documentation for your specific module
2. Look for the on() event listener method
3. Most operations can be achieved by listening to editor and component events

Common patterns:

// Listen for changes
editor.on('change', () => console.log('something changed'));

// Component lifecycle
editor.on('component:mount', (c) => console.log('component ready', c));
editor.on('component:update', (c) => console.log('component updated', c));

If you're still stuck:

• Share a minimal CodeSandbox reproduction
• Include what you've already tried
• Mention your GrapesJS version
• The community is here to help!