got "0xNaN" when rlp decode number field

[eiTT-01]

Description

When I try to decode a raw tx and then retrive its transaction id or singer, I just got null. After that I found it's caused by rlp decode.

Actual behavior

let clauses = [{
    to: '0x7567d83b7b8d80addcb281a71d54fc7b3364ffed',
    value: 0,
    data: '0x'
}]

let body = {
    chainTag: 0x9a,
    blockRef: '0x0000000000000000',
    expiration: 32,
    clauses: clauses,
    gasPriceCoef: 0,
    gas: 21000,
    dependsOn: null,
    nonce: 12345678
}

let tx = new Transaction(body)
let signingHash = cry.blake2b256(tx.encode())
tx.signature = cry.secp256k1.sign(signingHash, /* private key here */)

let raw = tx.encode()
let decoded = Transaction.decode(raw)

Decoded Transactin:

{
  "body": {
    "chainTag": 154,
    "blockRef": "0x0000000000000000",
    "expiration": 32,
    "clauses": [
      {
        "to": "0x7567d83b7b8d80addcb281a71d54fc7b3364ffed",
        "value": "0xNaN", // wrong
        "data": "0x"
      }
    ],
    "gasPriceCoef": "0xNaN", // wrong
    "gas": 21000,
    "dependsOn": null,
    "nonce": 12345678,
    "reserved": []
  },
  "signature": / * sig buffer */
  }
}

Suggestion

update rlp.ts file:

#89 const bn = new BigNumber('0x' + buf.toString('hex'))

to:

#89 const bn = new BigNumber(buf.toString('hex'), 16)