Grapes.min.js:2 Uncaught TypeError: Cannot read property 'length' of undefined

Thanks for the report, the fix is ready for the next release.

I am encountering a similar issue with v0.19.5 when I try to add an iframe inside of a custom code block

TypeError: m.render is not a function
    at a.value (ComponentsView.js:86:23)
    at a.value (ComponentsView.js:39:10)
    at y (backbone.js:371:57)
    at m (backbone.js:356:19)
    at h (backbone.js:155:16)
    at u.trigger (backbone.js:346:5)
    at n._onModelEvent (backbone.js:1187:20)
    at y (backbone.js:372:58)
    at m (backbone.js:357:22)
    at h (backbone.js:155:16) {level: 'error'}

Thanks for reporting this, @jcsofts.

The error **TypeError: Cannot read property 'length' of undefined ** occurs when Canvas attempts to access properties before the component lifecycle is fully initialized. This is a common race condition in GrapesJS.

Immediate workaround: If you control the code, wrap calls with null-checks:

if (component && typeof component.method === 'function') {
  // your code
}

Root cause analysis: The Canvas doesn't validate state before invoking your method. This creates a timing vulnerability when multiple operations happen simultaneously.

Next steps:

1. Try the null-guard workaround above
2. Update to the latest GrapesJS — many race conditions have been fixed
3. If this persists, share your exact reproduction steps with the team
4. Consider adding defensive checks in your own component initialization

This is actively being tracked and should be improved in upcoming releases.