Usage in React Native

[YannisDC]

Since crypto doesn't work in react native apparently I tried using react-native-crypto and installed it as suggested.

However I get the same error saying: Unable to resolve module crypto from <PROJECTROOT>/node_modules/bitcore-lib/lib/crypto/hash.js

Is there any way to circumvent this?

[Loyz07]

Same issue. We manage to install react-native-crypto but we've got a new error : undefined is not a function (evaluating BufferUtil.isBuffer(argument))

[seanavery]

@YannisDC @Loyz07 I am also working around this.

I have used this hack: https://github.com/mvayngrib/rn-nodeify and it seems to work with "browserifying" node's crypto library, also web3 and its dependencies.

However, I am still having issues with eth-lightwallet. I have to import from the ./index instead of the minified js dist.

Also exploring this alternative: https://github.com/philikon/ReactNativify

[seanavery]

@Loyz07 Were you able to sort out the undefined BufferUtil, I am having the same issue.

Seems to be a problem with the bitcore/lib/util/preconditions.js

Some people have had success by hacking the file as such:

var buffer = require('buffer');
        if (!(buffer.Buffer.isBuffer(argument) || argument instanceof Uint8Array)){
          throw new errors.InvalidArgumentType(argument, type, argumentName);
        }
        // var BufferUtil = require('./buffer');
        // if (!BufferUtil.isBuffer(argument)) {
        //   throw new errors.InvalidArgumentType(argument, type, argumentName);
        // }

However, this is not working for me...

[Loyz07]

@SeanAvery No sorry. It seems to be a problem with rn-nodeify that doesn't polyfill correctly Buffer module.

We are working on an other solution with Web3J and a native module since no solution is found for this issue.

[pablohern427]

Any workarounds found for this? Currently seeing the same issue as original post

[alex-miller-0]

I'm new to react-native so can't provide a ton of deep insight, but I run into similar issues just trying to get crypto functions working.

Since crypto is a node package and not supported by react-native, you will need to use rn-noedify and run the following postinstall script:

node_modules/.bin/rn-nodeify --install assert,buffer,crypto,events,process,stream,vm --hack

Or whatever combination of packages you want. If you want to install all node packages, you can run:

node_modules/.bin/rn-nodeify --install --hack

As @Loyz07 noted, this will not resolve the Buffer module properly. rn-nodeify will populate your root project directory with a file called shim.js. You may need to import this when using crypto.

let crypto = require('crypto');
import '../shim.js'

I believe the above is actual an aliased version of react-native-crypto, which you will also need to have installed and linked.