added a failing case and fixed it by refactoring everything to strings

test/unit/util_test.js

@@ -25,12 +25,26 @@ describe('util', function() {
     })
   })
   describe('parseBalance', function() {
-    it('should render 0.01 eth correctly', function() {
+    it('should render 12.023 eth correctly', function() {
       const input = 'A6DA46CCA6858000'
       const output = util.parseBalance(input)
       assert.deepEqual(output, ['12', '023'])
     })
   })
+  describe('parseBalance', function() {
+    it('should render 0.0000000342422 eth correctly', function() {
+      const input = '0x7F8FE81C0'
+      const output = util.parseBalance(input)
+      assert.deepEqual(output, ['0', '0000000342422'])
+    })
+  })
+  describe('parseBalance', function() {
+    it('should render 0 eth correctly', function() {
+      const input = '0x0'
+      const output = util.parseBalance(input)
+      assert.deepEqual(output, ['0', '0'])
+    })
+  })
 
   describe('addressSummary', function() {
     it('should add case-sensitive checksum', function() {

ui/app/util.js

@@ -85,22 +85,20 @@ function weiToEth(bn) {
 
 // Takes  hex, returns [beforeDecimal, afterDecimal]
 function parseBalance(balance) {
-  if (!balance || balance === '0x0') return ['0', '0']
-  var wei = numericBalance(balance).toString(10)
-  var eth = String(wei/valueTable['wei'])
-  var beforeDecimal = String(Math.floor(eth))
-  var afterDecimal
-  if(eth.indexOf('.') > -1){
-    afterDecimal = eth.slice(eth.indexOf('.') + 1)
-  }else{
-    afterDecimal = '0'
-  }
+  let beforeDecimal, afterDecimal
+  let wei = numericBalance(balance).toString()
+  let 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)
+  console.log(parsed)
   var beforeDecimal = parsed[0]
   var afterDecimal = parsed[1]
   var formatted = "None"