ArrayBuffer -> Blob?

[Alch-Emi]

Hello!

I was wondering if there's any way to turn an ArrayBuffer into a Blob. If I understand correctly, the JavaScript implementation of new Blob(...) allows for passing an array of blob parts, which can include ArrayBuffer (js) and ArrayBufferView (js). I don't see anything similar in the Web.File.Blob docs though, so I was wondering if there's a recommended way to do this.

My use case, in case of XY problems: I'm downloading an encrypted file using purescript-fetch, then decrypting it using purescript-subtlecrypto, which yields an ArrayBuffer (which I have a known image/* MIME for) that I want to display to the user. I know I could use data urls, but I'd like to avoid the memory/cpu overhead if possible.

Also, I'm a bit of a purescript novice, so apologies in advance if I've missed something that's obvious to more experienced users.

Thanks for your help!

[garyb]

No, I don't think you've missed anything - or if you have, I have too 😄 - I think we are indeed lacking a constructor for that case.

There's probably a couple of variations that are missing - if we wanted to support creating a Blob from multiple parts we'd have to introduce a BlobPart type and some coercion functions. Would also need to change the FFI implementation a bit if we wanted to support the endings option.