Propage h5wasm errors to viewer about h5web

[bmaranville]

Opt-in to throwing error handler is available new release https://github.com/usnistgov/h5wasm/releases/tag/v0.7.2

[axelboc]

Apparently, exception handling is disabled in Emscripten by default. So it might simply be a matter of compiling h5wasm with flag -fwasm-exceptions.

[bmaranville]

By default, the HDF5 library error handler function prints to the error stream for every error. This is what is ending up in the users' console. That error handler function can be overridden, but it would require writing a new error handler function in C, and setting that as the default. There don't seem to be a lot of examples of custom error handler functions.

It's possible that the C++ API for for HDF5 has exception handling in it already - but migrating to that API from the C API would also be some work.

[bmaranville]

There is a PR brewing for raising exceptions in h5wasm here: usnistgov/h5wasm#68
I still have to write some tests, but it seems to work as expected.

[axelboc]

Fantastic!! Thanks for looking into this 💯