Implement fast keystroke auto linking of link–like text content in editable

[oleq]

A followup of https://github.com/ckeditor/ckeditor5-link/issues/2#issuecomment-240374891.

Automated and "on keystroke" linking pasted and typed URLs. E.g. if you paste a URL, then it can be safely autolinked. But if you paste a lot of content or you typed that URL in some specific way and it wasn't autolinked, just press CTRL+K having selection in the URL text and that URL should be converted into a link.

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The whole idea comes down to two cases:

Basic auto linking

As in https://github.com/ckeditor/ckeditor5-link/issues/6. If pasted content matches link pattern, it should be converted into <a href="http://foo">http://foo</a>. If not, or there's something else beside white spaces in the clipboard, it should be pasted as plain text.

Keystroke auto linking

If there's more in the clipboard (or simply in the content) than just a link, user can move selection to the link text, and use keyboard shortcut to automatically convert it into an <a> tag.

[Reinmar]

The autolinking feature will make this one either totally unnecessary or a low-priority one. It depends on autolinking aggressiveness which is a think that needs some attention. We cannot autolink things which users may not want to link – e.g. things that were already unlinked :D.

I mentioned this case because I saw that GDocs can do it and I've been using it myself. IIRC, GDocs isn't autolinking when you paste content and often I make a draft of some article outside and then paste it. So if we follow GDocs behaviour, this feature would be nice.

This feature could also be nice if someone didn't want to enable autolinking. I know that some auto-corrections can be frustrating – although, usually it's about correcting the first letter in a sentence, or similar uncertain things – linking sounds safer.

[oleq]

This feature could also be nice if someone didn't want to enable autolinking. I know that some auto-corrections can be frustrating

👏

I think that link feature will have some nice tools to check what is around the selection in editable anyway, so this could be a very easy thing to implement using that API.