this.db.transaction is not a function
While using indexdb, doing a search blows up randomly with this.db.transaction is not a function.
It smells like it might be a race condition with this? https://github.com/nextapps-de/flexsearch/blob/master/src/db/indexeddb/index.js#L359
I'm currently indexing while searching.
Also facing a similar issue, which seems to appear when calling Document.clear, which I believe calls IdxDB.clear. I notice that a version change could trigger this.db being set to null in IdxDB.close(), but I don't think that's happening in our case.
I've removed this line in the latest version but probably it does not fix your issue. I will further investigate into the transaction handling soon.