move util functions to util.js

1 files changed, 31 insertions, 0 deletions

diff --git a/app/scripts/lib/util.js b/app/scripts/lib/util.js
index bddd60ee8..70390e95c 100644
--- a/app/scripts/lib/util.js
+++ b/app/scripts/lib/util.js
@@ -1,8 +1,39 @@
+const ethUtil = require('ethereumjs-util')
+const BN = ethUtil.BN
+
 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) {
+  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)
+}