code: function(rawTx) {
    const rawTxMutation = Object.assign({}, rawTx);
  
    // fix rawTx gaslimit
    if (typeof rawTxMutation.gas !== 'undefined') {
      rawTxMutation.gasLimit = rawTxMutation.gas;
      delete rawTxMutation.gas;
    }
  
    // fix data by prefixing it with zero
    if (typeof rawTxMutation.data !== 'undefined'
        && rawTxMutation.data.slice(0, 2) !== '0x') {
      rawTxMutation.data = '0x' + rawTxMutation.data;
    }
  
    // return new mutated raw tx object
    return rawTxMutation;
  }
docs: fix ethereumjs-tx rawTx object