@backt/protocol/lib/utils.js

Backt smart contracts implementation

'use strict';

var BigNumber = require('bignumber.js');
BigNumber.config({ DECIMAL_PLACES: 30 });

var EMPTY_ACCOUNT = '0x' + '0'.repeat(40);

/**
 * Feed values must be passed around as Bignumbers or strings due to the 15
 * significant digit limitation of Javascript numbers.
 *
 * Functions expecting numbers should use this assertion to guarantee inputs.
 */
var assertBigNumberOrString = function assertBigNumberOrString(number) {
  if (number.isBigNumber === false && typeof number !== 'string') {
    throw new Error('number can only be a BigNumber or String');
  }
};

/**
 * Convert number to format expected in the smart contract - Adjust it by
 * numDecimals places such that 11.8209 becomes 11820900000000000000 if
 * numDecimals is 18.
 *
 * @param number BigNumber|String Actual number to be converted
 * @param numDecimals Number of decimals to adjust (see Feeds.sol decimals)
 * @return BigNumber contract format value
 */
var toContractBigNumber = function toContractBigNumber(number, numDecimals) {
  assertBigNumberOrString(number);
  var bn = new BigNumber(number);
  return bn.times(Math.pow(10, numDecimals));
};

/**
 * The reverse of toContractBigNumber (See above)
 *
 * @param contractBigNumber BigNumber Contract format number to be adjusted
 * @param numDecimals Number of decimals to adjust (see Feeds.sol decimals)
 * @return BigNumber original value
 */
var fromContractBigNumber = function fromContractBigNumber(contractBigNumber, numDecimals) {
  assertBigNumberOrString(contractBigNumber);
  return contractBigNumber.div(new BigNumber(10).pow(numDecimals));
};

var nowSecs = function nowSecs() {
  return Math.floor(Date.now() / 1000);
};

var isValidMarketId = function isValidMarketId(id) {
  return (/^[A-Za-z]+_[A-Z]+_[A-Z]+$/i.test(id)
  );
};

var isEthereumAddress = function isEthereumAddress(addr) {
  return (/0x[a-f0-9]{40,}/i.test(addr)
  );
};

var txGas = function txGas(txReceipt) {
  return txReceipt.receipt.gasUsed;
};

// extract the gas cost in wei for a given transaction
var txGasCost = function txGasCost(txHash, web3) {
  var _web3$eth$getTransact = web3.eth.getTransaction(txHash),
      gasPrice = _web3$eth$getTransact.gasPrice;

  var _web3$eth$getTransact2 = web3.eth.getTransactionReceipt(txHash),
      gasUsed = _web3$eth$getTransact2.gasUsed;

  return gasPrice.times(gasUsed);
};

/**
 * Determine if the given status is a failure status or not.
 * Different Ethereum clients return the status in different ways.
 * So check all the possible formats of a success status here.
 *
 * @param string|number Transaction status as stored in a transaction receipt object
 * @return bool  True if the transaction failed
 */
var txFailed = function txFailed(status) {
  return status !== 1 && status !== '0x1' && status !== '0x01';
};

/**
 * Mapping of values returned by ContractForDifference.status() function.
 */
var STATUS = {
  CREATED: 0,
  INITIATED: 1,
  SALE: 2,
  CLOSED: 3
};

module.exports = {
  assertBigNumberOrString: assertBigNumberOrString,
  fromContractBigNumber: fromContractBigNumber,
  isEthereumAddress: isEthereumAddress,
  isValidMarketId: isValidMarketId,
  nowSecs: nowSecs,
  toContractBigNumber: toContractBigNumber,
  txGas: txGas,
  txGasCost: txGasCost,
  txFailed: txFailed,
  EMPTY_ACCOUNT: EMPTY_ACCOUNT,
  STATUS: STATUS
};