Bitcoin Development Kit - React Native Module

As far as I understand, bdk-rn currently allows to create a wallet only from a mnemonic. Would it make sense to have createWallet taking a simple descriptor and expose generateExtendedKey and restoreExtendedKey so that the client app has more control?

Is it what this comment is about? https://github.com/LtbLightning/bdk-rn/blob/edb9ebf64c8012bb89f56bdc17df5f645b17e8d3/android/src/main/java/io/ltbl/bdkrn/BdkFunctions.kt#L104

With the way the switch/case block is written in createDescriptor, the shp2wpkh and p2shp2wpkh cases result in a descriptor without a closing parenthesis e.g. sh(wpkh(...). This change is a refactoring of the switch case block to enable constructing descriptor for all cases correctly, and also improve maintainability and readability.

Currently, bdk-rn only store plain data (seedphase, password,..) in localstorage that cause critical security issue. I glad to help you make change via PR, my plan is switch from localstorage to react-native-keychain, but what do you think about it?

If everything is clear, I will create a PR for it.

This PR:

• Updates the response pattern to be as follows:

const result = BdkRn.generatemnemomic();
if (result.isErr()) {
    console.error(result.error.message); // "error message"
    return;
}
const mnemonic = result.value;

• Adds @synonymdev/result dependency to package.json.
• Removes & Replaces previous Response pattern with @synonymdev/result where needed.
• Updates README.md.
• This closes #28

Do you have any thoughts/feelings on updating the method return response for increased clarity on returned types?

At Synonym we use the following: https://www.npmjs.com/package/@synonymdev/result

Example Usage:

const randomDataCheck = (data): Result<string> => {
    if (!data) return err('No data available');
    return ok('Data was provided');
};

const result = randomDataCheck('Some data');
if (result.isErr()) {
    console.error(result.error.message); // "error message"
    return;
}
const dataCheckRes = result.value;

This way we always know what's getting returned and it ensures we're checking each response before proceeding. It also helps keep our responses consistent across projects. I would be happy to create a PR with these changes if you believe it would benefit the bdk-rn library.

In createDescriptor:

Remove useMnemonic argument.
instead modify logic to:
use xpriv if set, otherwise, use mnemonic. Throw error if none or both are set.
 if mnemonic flow is chosen network should be specified but password can be optional
 The rest of the arguments should use default values.

yarn compile is currently failing due to typing errors. This prevents installation of the package since compile is called by prepare.

Here are the errors I was getting:

> yarn compile

src/index.ts:92:58 - error TS2322: Type 'string | undefined' is not assignable to type 'string'.
  Type 'undefined' is not assignable to type 'string'.

92         xprv = await (await this.generateXprv({ network, mnemonic, password })).data;
                                                            ~~~~~~~~

  src/lib/interfaces.ts:17:3
    17   mnemonic: string;
         ~~~~~~~~
    The expected type comes from property 'mnemonic' which is declared here on type 'CreateExtendedKeyRequest'

src/index.ts:123:30 - error TS2532: Object is possibly 'undefined'.

123         if (thresold == 0 || thresold > publicKeys?.length + 1) throw 'Thresold value in invalid.';
                                 ~~~~~~~~

src/index.ts:123:41 - error TS2532: Object is possibly 'undefined'.

123         if (thresold == 0 || thresold > publicKeys?.length + 1) throw 'Thresold value in invalid.';
                                            ~~~~~~~~~~~~~~~~~~

src/index.ts:153:28 - error TS2532: Object is possibly 'undefined'.

153       if (useDescriptor && descriptor?.split(' ').length > 1) throw 'Descriptor is not valid.';
                               ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

src/lib/utils.ts:1:16 - error TS7016: Could not find a declaration file for module 'is_js'. '/Users/tomesterez/projects/bdk-rn/node_modules/is_js/is.js' implicitly has an 'any' type.
  Try `npm i --save-dev @types/is_js` if it exists or add a new declaration (.d.ts) file containing `declare module 'is_js';`

1 import is from 'is_js';
                 ~~~~~~~


Found 5 errors.

A simpler API could be to use descriptor if set, otherwise, use mnemonic. Throw if none or both are set.

Originally posted by @testerez in https://github.com/LtbLightning/bdk-rn/pull/6#discussion_r930035906

For createWallet:

Remove useDescriptor argument. instead modify logic to use descriptor if set, otherwise, use mnemonic. Throw error if none or both are set. if mnemonic flow is chosen network should be specified but password can be optional the rest of the arguments should use default values.

• change init wallet to createWallet with enhanced interface
• createWallet can use mnemonic or descriptor
• added methods generateMnemonic, createExtendedKey and createXprv
• Multiple types of descriptors can be created with createDescriptor method

Description

This PR add getTransactions function which return all transactions of wallet, include confirmed and unconfirmed transactions

Example response

{
   "confirmed":{
      "29b326a7b5fa83c7a910ed4ffe6631f3e35cb812b9b2ba511c20346ba9f596d5":{
         "fees":"18978",
         "height":"2254565",
         "received":"269152",
         "sent":"0",
         "timestamp":"1654657187"
      },
      "3e323b658af359fcd886a422c2b7ea149fcafe1434278005e020cac4f4ac8ad6":{
         "fees":"141",
         "height":"2254398",
         "received":"72000",
         "sent":"0",
         "timestamp":"1654568599"
      },
      "a429080fee431be80056a87cfbc784468c628c4cc9d64f4a207f23776874cf90":{
         "fees":"141",
         "height":"2254563",
         "received":"10000",
         "sent":"0",
         "timestamp":"1654656069"
      }
   },
   "unconfirmed":{
      
   }
}

Checklists

Platforms

• [ ] iOS
• [x] Android

New features

• [x] getTransactions

Issues

bdk-swift always return null transaction, I'm not familiar with Swift, but I think the issue is from bdk-swift itself

Currently, CreateDescriptors creates descriptors based on the path and script type specified by the user. This is probably not as useful as having the ability to create a descriptor based on a standard BIP. Because it assumes that the user knows the path and script type for a specific wallet type.

It will be more useful to have the ability to create descriptors for standard wallet types(bip44/49/84) based on BDK templates already available:

https://docs.rs/bdk/latest/bdk/descriptor/template/index.html

Templates currently available:

Bip44 BIP44 template. Expands to pkh(key/44'/{0,1}'/0'/{0,1}/) Bip44Public BIP44 public template. Expands to pkh(key/{0,1}/) Bip49 BIP49 template. Expands to sh(wpkh(key/49'/{0,1}'/0'/{0,1}/)) Bip49Public BIP49 public template. Expands to sh(wpkh(key/{0,1}/)) Bip84 BIP84 template. Expands to wpkh(key/84'/{0,1}'/0'/{0,1}/) Bip84Public BIP84 public template. Expands to wpkh(key/{0,1}/) P2Pkh P2PKH template. Expands to a descriptor pkh(key) P2Wpkh P2WPKH template. Expands to a descriptor wpkh(key) P2Wpkh_P2Sh P2WPKH-P2SH template. Expands to a descriptor sh(wpkh(key))

Reference for descriptors: https://github.com/bitcoin/bitcoin/blob/master/doc/descriptors.md

It seems omitting the network parameter on getMnemonic() method results in a blocking error: Parameter specified as non-null is null.

Is there a reason setting the network is required at this stage?

Error on iOS: "Code: Init Wallet Error Message: The operation couldn’t be completed. (bdk_rn.BdkError error 26.)" Error on Android: "Code: Init Wallet Error Message: Descriptor(Key(InvalidNetwork))"

Transaction creation, signing and broadcast should be separate methods. This will allow more flexibility in user journeys as well as better error handling. This will also be required when doing multisig transactions.

Current implementation uses Android and iOA binaries as core modules for providing bdk functionality.

Do a Proof of concept to explore use of JSI interface to C++ as a alternate mechanism instead of using platform binaries.

This has a number of advantages:

• Eliminates constraints of RN bridge
• Will allow reuse of bdk ffi rust code directly thus providing more api
• Will reduce effort and maintenance in using native wrapper code in Android and iOS
• Performance improvements
• Eliminate cold start time