Progress!

This is the app, very basic so far: https://github.com/ipfs-shipyard/js-libp2p-react-native

Oh good, react native doesn't support passing async generators to for await..of, fun times - facebook/react-native#27432

Actually it sort of does but generators don't appear to have the Symbol.asyncIterator property.

The crypto situation is pretty dire, from what I can gather there's no SubtleCrypto support and Facebook's response to questions about adding it were lukewarm.

This rules out simply following the browser path in modules with node/browser support since they depend on SubtleCrypto.

We could shim in pure-js versions of everything but crypto is such a bottleneck for us that doing everything in js on your phone is likely to melt it.

The community response yielded react-native-webcrypto but it's incomplete and only works on Android.

react-native-webview-crypto is an interesting hack though the library it depends on has a showstopping bug that's only had a PR to fix it open for three years. It also involves stringifying and copying all data to be encrypted/decryped to/from a webview - I haven't measured it but common sense says that will not be a performant approach.

We could patch the library to fix the bug and transfer the Uint8Arrays but that will break clever memory optimisations elsewhere because the underlying Uint8Arrays will become unusable after the transfer.

The other approach is to follow the node path instead and use rn-nodeify to shim node core modules in where necessary.

This opens up the possibility of using react-native-quick-crypto which does crypto in C/C++ so would be preferable.

Unlike most of the other crypto libraries here, quick-crypto appears to still be under development so that's heartening.

Actually the sweet spot might be to shim SubtleCrypto with @peculiar/webcrypto - it uses node's crypto module internally which can then be resolved to react-native-quick-crypto.

Getting there, it can dial the bootstrappers now:

Circuit relay works: