dexie-export-import exports corrupt blobs

[zewt]

I'm getting corrupt blobs from dexie-export-import:

https://gist.github.com/zewt/0ef5e39c535c3ab7abbd6b855dab9a92

This exports two rows, one with "1234" and one with "abcd". The exported data looks like "MTIzNGFiY2Q=", which is "1234abcd".

This looks like where the broken data is created:

https://github.com/dexie/Dexie.js/blob/master/addons/dexie-export-import/src/tson.ts#L73

        typeSpec.finalize(b, allChunks.slice(b.start, b.end));

b looks like { type: { mime", data: { start: 100, end: 200 } }, so this calls slice(undefined, undefined), which just makes a copy of allChunks.

(Tangentally, I'm confused at the global state in blobsToAwait. Wouldn't this corrupt exports if multiple databases are exported in parallel?)