Is there any way to recover data in a TextEdit file that was closed with 'revert changes'?

When I returned to a TextEdit doc a huge amount of white space had been added -- as if I had hit <Return> for hours. In fact it was adding white space when I opened my MacBook with TextEdit on-screen. I somehow got it to stop.

I thought that closing the document with 'Revert changes' would allow me to then reopen the document without all that white space -- i.e., that it would reopen in the condition it had been in before whatever happened to create all that white space occurred.

I also was under the impression that TextEdit autosaves as you work -- i.e., without having to actively save the document. The reason I thought that is because it always seemed to do that when I closed TextEdit -- i.e., it saved whatever I had not actively saved. I saw that that unsaved text was retained when I next opened TextEdit.

But when I reopened the document I had closed with 'revert changes' all the data I had put in the document since I last actively saved it was no longer in it.

So now I am wondering -- does TextEdit only 'save to disk' what you actively 'save' and otherwise retain what you didn't actively save in memory only?

And is there any way to get the lost data back?

Thanks.

Mac OS 10.14.3 (Mojave)