MyCrypto/common/selectors/transaction/transaction.ts

import { AppState } from 'reducers';
import { getCurrentTo, getCurrentValue } from './current';
import { getFields } from './fields';
import { makeTransaction, IHexStrTransaction } from 'libs/transaction';
import EthTx from 'ethereumjs-tx';
import { getUnit } from 'selectors/transaction/meta';
import { reduceToValues, isFullTx } from 'selectors/transaction/helpers';
import {
  getGasPrice,
  getGasLimit,
  getDataExists,
  getSerializedTransaction,
  getValidGasCost,
  isEtherTransaction
} from 'selectors/transaction';
import { Wei } from 'libs/units';
import { getTransactionFields } from 'libs/transaction/utils/ether';
import { getNetworkConfig } from 'selectors/config';

const getTransactionState = (state: AppState) => state.transaction;

export interface IGetTransaction {
  transaction: EthTx;
  isFullTransaction: boolean; //if the user has filled all the fields
}

const getTransaction = (state: AppState): IGetTransaction => {
  const currentTo = getCurrentTo(state);
  const currentValue = getCurrentValue(state);
  const transactionFields = getFields(state);
  const unit = getUnit(state);
  const reducedValues = reduceToValues(transactionFields);
  const transaction: EthTx = makeTransaction(reducedValues);
  const dataExists = getDataExists(state);
  const validGasCost = getValidGasCost(state);
  const isFullTransaction = isFullTx(
    state,
    transactionFields,
    currentTo,
    currentValue,
    dataExists,
    validGasCost,
    unit
  );

  return { transaction, isFullTransaction };
};

const nonStandardTransaction = (state: AppState): boolean => {
  const etherTransaction = isEtherTransaction(state);
  const { isFullTransaction } = getTransaction(state);
  const dataExists = getDataExists(state);
  return isFullTransaction && dataExists && etherTransaction;
};

const getGasCost = (state: AppState) => {
  const gasPrice = getGasPrice(state);
  const gasLimit = getGasLimit(state);
  return gasLimit.value ? gasPrice.value.mul(gasLimit.value) : Wei('0');
};

const serializedAndTransactionFieldsMatch = (state: AppState, isLocallySigned: boolean) => {
  const serialzedTransaction = getSerializedTransaction(state);
  const { transaction, isFullTransaction } = getTransaction(state);
  if (!isFullTransaction || !serialzedTransaction) {
    return false;
  }
  const t1 = getTransactionFields(transaction);
  // inject chainId into t1 as it wont have it from the fields
  const networkConfig = getNetworkConfig(state);
  if (!networkConfig) {
    return false;
  }
  const { chainId } = networkConfig;
  t1.chainId = chainId;

  const t2 = getTransactionFields(makeTransaction(serialzedTransaction));
  const checkValidity = (tx: IHexStrTransaction) =>
    Object.keys(tx).reduce(
      (match, currField: keyof IHexStrTransaction) => match && t1[currField] === t2[currField],
      true
    );
  //reduce both ways to make sure both are exact same
  const transactionsMatch = checkValidity(t1) && checkValidity(t2);
  // if its signed then verify the signature too
  return transactionsMatch && isLocallySigned
    ? makeTransaction(serialzedTransaction).verifySignature()
    : true;
};

export {
  getTransaction,
  getTransactionState,
  getGasCost,
  nonStandardTransaction,
  serializedAndTransactionFieldsMatch
};