isOpfsSupported converts a function to a string to create a JS source string

which is then loaded into a worker.

If this code is run through certain code transforms (e.g. tsc with target of es2015), the inner function's string representation can become invalid worker code. In my project, inner.toString() === 'e', so the resulting worker source was (e)().then(postMessage) (and e's definition is outside of the worker) – attempting to use isOpfsSupported raises an error because e.then is not defined.

I think with target = es2015, any async function would become invalid: demo.

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This is an issue for me because I'm using your dialect-wasqlite-worker (which is otherwise great, ty), which has an unskippable check to isOpfsSupported when trying to use OPFS.

I don't need a fix urgently because I'm probably just going to patch dialect-wasqlite-worker to unblock myself (I can assume OPFS is available in my app), but thought I'd bring this up as a potential pitfall.