Remove direct crypto module dependency to support React Native

[kamescg]

Describe the bug
The crypto module breaks React Native.

Would be great to use the shim provided by ethers to add the essential crypto methods.

[kamescg]

Something odd is happening, because I have ethers already installed too.

When I include identity-wallet it breaks the crypto require for ethers too. However, without identity wallet, the ethers modules works as expected.

So, maybe because identity-wallet doesn't require the shim it appears to rewrite stuff and break ethers too?

[kamescg]

Removing crypto to create the sha256 hash will fix the problem. Got ethers and identity-wallet working in tandem now in a React Native env.

https://github.com/3box/identity-wallet-js/blob/11d7fdb7590c1e7fd63490ad02e81bebab25c87c/src/utils.js#L13

[kamescg]

I realize now it's a futile effort, because the HDNode module use random-bytes which I thought ethers it was shimming, but it's not.

So probably not worth the effort to remove crypto because still need the random-bytes in RN.

Maybe WASM modules to replace all the node/crypto stuff is a smart long-term move for a React Native environment?

[oed]

Thanks for reporting. You're right, we should probably just use js-sha256 instead. As for problems with random-bytes, I've had success with rn-nodeify before.

[kamescg]

Quick heads up that using the dist version fixed all the React Native Metro crypto bundler problems for me. I don't if you guys want to keep non-dist version (for tree shaking) or not, but maybe we can get a React Native fix inlcuded somehow?

import {utils} from 'ethers/dist/ethers';
...
this._baseNode = utils.HDNode.fromSeed(this._seed).derivePath(BASE_PATH);

[oed]

@kamescg we are no longer importing the entire ethers library for size reasons. Did you try using rn-nodeify as I mentioned above?

[kamescg]

Yes. My whole app is nodified/cryptoified. I'm running ethers nicely.

It's only this library throwing import errors and I believe it's because the Metro compile is not catching the crypto module in 3Box and re-setting to react-native-crypto.

[kamescg]

It's an old fix from awhile back => ethers-io/ethers.js#268 (comment)

I'm gonna make sure I'm running the latest and see if I still have any issues.. I think my identity-wallet version might be behind an update or too.

[oed]

catching the crypto module in 3Box

Wait are you running 3box, or IdentityWallet in RN? The former will likely not work at all.

[kamescg]

IdentityWallet. That was a typo.

I'm aware of all the 3Box React Native issues and I'm not going paid enough to want to deal with that headache :)