metamask-extension/ui/app/util.js

const ethUtil = require('ethereumjs-util')

var valueTable = {
  wei: '1000000000000000000',
  kwei: '1000000000000000',
  mwei: '1000000000000',
  gwei: '1000000000',
  szabo: '1000000',
  finney: '1000',
  ether: '1',
  kether: '0.001',
  mether: '0.000001',
  gether: '0.000000001',
  tether: '0.000000000001',
}
var bnTable = {}
for (var currency in valueTable) {
  bnTable[currency] = new ethUtil.BN(valueTable[currency], 10)
}

module.exports = {
  valuesFor: valuesFor,
  addressSummary: addressSummary,
  isAllOneCase: isAllOneCase,
  isValidAddress: isValidAddress,
  numericBalance: numericBalance,
  parseBalance: parseBalance,
  formatBalance: formatBalance,
  generateBalanceObject: generateBalanceObject,
  dataSize: dataSize,
  readableDate: readableDate,
  ethToWei: ethToWei,
  weiToEth: weiToEth,
  normalizeToWei: normalizeToWei,
  normalizeEthStringToWei: normalizeEthStringToWei,
  normalizeNumberToWei: normalizeNumberToWei,
  valueTable: valueTable,
  bnTable: bnTable,
}

function valuesFor (obj) {
  if (!obj) return []
  return Object.keys(obj)
    .map(function (key) { return obj[key] })
}

function addressSummary (address) {
  if (!address) return ''
  var checked = ethUtil.toChecksumAddress(address)
  return checked ? checked.slice(0, 2 + 8) + '...' + checked.slice(-4) : '...'
}

function isValidAddress (address) {
  var prefixed = ethUtil.addHexPrefix(address)
  return (isAllOneCase(prefixed) && ethUtil.isValidAddress(prefixed)) || ethUtil.isValidChecksumAddress(prefixed)
}

function isAllOneCase (address) {
  if (!address) return true
  var lower = address.toLowerCase()
  var upper = address.toUpperCase()
  return address === lower || address === upper
}

// Takes wei Hex, returns wei BN, even if input is null
function numericBalance (balance) {
  if (!balance) return new ethUtil.BN(0, 16)
  var stripped = ethUtil.stripHexPrefix(balance)
  return new ethUtil.BN(stripped, 16)
}

// Takes eth BN, returns BN wei
function ethToWei (bn) {
  var eth = new ethUtil.BN('1000000000000000000')
  var wei = bn.mul(eth)
  return wei
}

// Takes BN in Wei, returns BN in eth
function weiToEth (bn) {
  var diff = new ethUtil.BN('1000000000000000000')
  var eth = bn.div(diff)
  return eth
}

// Takes  hex, returns [beforeDecimal, afterDecimal]
function parseBalance (balance) {
  var beforeDecimal, afterDecimal
  const wei = numericBalance(balance).toString()
  const trailingZeros = /0+$/

  beforeDecimal = wei.length > 18 ? wei.slice(0, wei.length - 18) : '0'
  afterDecimal = ('000000000000000000' + wei).slice(-18).replace(trailingZeros, '')
  if (afterDecimal === '') { afterDecimal = '0' }
  return [beforeDecimal, afterDecimal]
}

// Takes wei hex, returns "None" or "${formattedAmount} ETH"
function formatBalance (balance, decimalsToKeep) {
  var parsed = parseBalance(balance)
  var beforeDecimal = parsed[0]
  var afterDecimal = parsed[1]
  var formatted = 'None'
  if (decimalsToKeep === undefined) {
    if (beforeDecimal === '0') {
      if (afterDecimal !== '0') {
        var sigFigs = afterDecimal.match(/^0*(.{2})/) // default: grabs 2 most significant digits
        if (sigFigs) { afterDecimal = sigFigs[0] }
        formatted = '0.' + afterDecimal + ' ETH'
      }
    } else {
      formatted = beforeDecimal + '.' + afterDecimal.slice(0, 3) + ' ETH'
    }
  } else {
    afterDecimal += Array(decimalsToKeep).join('0')
    formatted = beforeDecimal + '.' + afterDecimal.slice(0, decimalsToKeep) + ' ETH'
  }
  return formatted
}

function generateBalanceObject (formattedBalance) {
  var balance = formattedBalance.split(' ')[0]
  var label = formattedBalance.split(' ')[1]
  var beforeDecimal = balance.split('.')[0]
  var afterDecimal = balance.split('.')[1]

  if (beforeDecimal === '0' && afterDecimal.substr(0, 5) === '00000') { balance = '< 0.00001' }

  return { balance, label }
}

function dataSize (data) {
  var size = data ? ethUtil.stripHexPrefix(data).length : 0
  return size + ' bytes'
}

// Takes a BN and an ethereum currency name,
// returns a BN in wei
function normalizeToWei (amount, currency) {
  try {
    return amount.mul(bnTable.wei).div(bnTable[currency])
  } catch (e) {}
  return amount
}

function normalizeEthStringToWei (str) {
  const parts = str.split('.')
  let eth = new ethUtil.BN(parts[0], 10).mul(bnTable.wei)
  if (parts[1]) {
    var decimal = parts[1]
    while (decimal.length < 18) {
      decimal += '0'
    }
    const decimalBN = new ethUtil.BN(decimal, 10)
    eth = eth.add(decimalBN)
  }
  return eth
}

var multiple = new ethUtil.BN('10000', 10)
function normalizeNumberToWei (n, currency) {
  var enlarged = n * 10000
  var amount = new ethUtil.BN(String(enlarged), 10)
  return normalizeToWei(amount, currency).div(multiple)
}

function readableDate (ms) {
  var date = new Date(ms)
  var month = date.getMonth()
  var day = date.getDate()
  var year = date.getFullYear()
  var hours = date.getHours()
  var minutes = '0' + date.getMinutes()
  var seconds = '0' + date.getSeconds()

  var dateStr = `${month}/${day}/${year}`
  var time = `${hours}:${minutes.substr(-2)}:${seconds.substr(-2)}`
  return `${dateStr} ${time}`
}