1 files changed, 44 insertions, 0 deletions
diff --git a/app/scripts/lib/util.js b/app/scripts/lib/util.js
new file mode 100644
index 000000000..6dee9edf0
--- /dev/null
+++ b/app/scripts/lib/util.js
@@ -0,0 +1,44 @@
+const ethUtil = require('ethereumjs-util')
+const assert = require('assert')
+const BN = require('bn.js')
+
+module.exports = {
+  getStack,
+  sufficientBalance,
+  hexToBn,
+  bnToHex,
+  BnMultiplyByFraction,
+}
+
+function getStack () {
+  const stack = new Error('Stack trace generator - not an error').stack
+  return stack
+}
+
+function sufficientBalance (txParams, hexBalance) {
+  // validate hexBalance is a hex string
+  assert.equal(typeof hexBalance, 'string', 'sufficientBalance - hexBalance is not a hex string')
+  assert.equal(hexBalance.slice(0, 2), '0x', 'sufficientBalance - hexBalance is not a hex string')
+
+  const balance = hexToBn(hexBalance)
+  const value = hexToBn(txParams.value)
+  const gasLimit = hexToBn(txParams.gas)
+  const gasPrice = hexToBn(txParams.gasPrice)
+
+  const maxCost = value.add(gasLimit.mul(gasPrice))
+  return balance.gte(maxCost)
+}
+
+function bnToHex (inputBn) {
+  return ethUtil.addHexPrefix(inputBn.toString(16))
+}
+
+function hexToBn (inputHex) {
+  return new BN(ethUtil.stripHexPrefix(inputHex), 16)
+}
+
+function BnMultiplyByFraction (targetBN, numerator, denominator) {
+  const numBN = new BN(numerator)
+  const denomBN = new BN(denominator)
+  return targetBN.mul(numBN).div(denomBN)
+}