Occasional stack trace error: Cannot read property 'on' of undefined

[CExJTian]

Hi there,

We are using ckeditor version 4.11.2 and noticed occasional stack trace in server log: TypeError: Cannot read property 'on' of undefined

It seems to be caused by following code in file ckeditor.js, line 351 - 352.

attachListener: function(a) {
    !this._.listeners && (this._.listeners = []);
    var b = Array.prototype.slice.call(arguments,
            1),
        b = a.on.apply(a, b);
    this._.listeners.push(b);
    return b
}

It would be great if it can be taken care of when a is undefined.

Thanks!

Type of report

Bug

Provide detailed reproduction steps (if any)

Expected result

No stack trace error

Actual result

TypeError: Cannot read property 'on' of undefined

Other details

• Browser: Chrome
• OS: Mac
• CKEditor version: 4.11.2

[Dumluregn]

Hello, thanks for creating this issue, could you give us some more details like when this error occurs? And if it can be reproduced in the current version, i.e. 4.12.1?

[aasiph]

For me the bug appears in chrome when changing editor mode to source and setting new data with event.editor.setData

editor.on('beforeSetMode', function(event) {
            var commentData;
             if ( event.data == 'source' ) {
                commentData = smileyHandler(event.editor.getData(),true);
                event.editor.setData(commentData);
             } else {
                commentData = smileyHandler(event.editor.getData(),false);
                event.editor.setData(commentData);
             }
         });

You can go through link http://www.aiglemedia.com/php/ajaxguestbook/ to verify the problem. Just click on add entry button and you will get the editor instance.

Also i see network activity of loading contents.css when switching to WYSIWYG mode.

And yes it appears in version 4.12.1 also which i have right now tested on local machine.

[Comandeer]

It seems that the issue is connected with the fact that initialisation of iframe-based editable, provided by wysiwygarea plugin, is asynchronous and part of it tries to finish after changing mode and destroying the iframe.

[GitLaser]

I also encountered this problem. How can I solve it