Large text hanging the page

[dkrahn]

Is this a bug report or feature request? (choose one)

🐞 Bug report | Other

💻 Version of CKEditor

From latest examples(https://ckeditor.com/ckeditor-5/#document)
Compared to CKEditor4 lastest examples (https://ckeditor.com/ckeditor-4/#document)

📋 Steps to reproduce

1. Have some huge text (Lorem ipsum >100 paragraphs)
2. Paste them in the editor
3. Select all the text
4. Apply some style(Ex. Bold)

✅ Expected result

Have CKEditor5 apply it as quick as CKEditor4.

❎ Actual result

CKEditor4 applies it instantly, while CKEditor5 takes a while, hanging the page.

📃 Other details that might be useful

I know CKEditor5 has a lot more constrains reflecting the changes into the model. But is seams that this could impact some cases with where the documents are big. For this reason I was split between bug and other, for it seams to be JavaScript performance limitation.

[oleq]

Related to https://github.com/ckeditor/ckeditor5-engine/issues/494 and #693. cc @Reinmar

[Reinmar]

We didn't make any research on this yet so I guess there are some low hanging fruits out there. Let's keep the discussion in https://github.com/ckeditor/ckeditor5-engine/issues/494

[Reinmar]

PS. Some initial profiling may help to understand what kind of issues we're dealing with. If you're struggling with performance issues in real use cases, you may try to dig into this.