Merge pull request #2818 from MetaMask/i2782-ethroundingerror

Fix rounding error in ether input on send screen

2 files changed, 20 insertions, 1 deletions

diff --git a/ui/app/send.js b/ui/app/send.js
index e59c1130e..09c9e03d4 100644
--- a/ui/app/send.js
+++ b/ui/app/send.js
@@ -247,10 +247,26 @@ SendTransactionScreen.prototype.onSubmit = function () {
   const recipient = state.recipient || document.querySelector('input[name="address"]').value.replace(/^[.\s]+|[.\s]+$/g, '')
   const nickname = state.nickname || ' '
   const input = document.querySelector('input[name="amount"]').value
+  const parts = input.split('')
+
+  let message
+
+  if (isNaN(input) || input === '') {
+    message = 'Invalid ether value.'
+    return this.props.dispatch(actions.displayWarning(message))
+  }
+
+  if (parts[1]) {
+    var decimal = parts[1]
+    if (decimal.length > 18) {
+      message = 'Ether amount is too precise.'
+      return this.props.dispatch(actions.displayWarning(message))
+    }
+  }
+
   const value = util.normalizeEthStringToWei(input)
   const txData = document.querySelector('input[name="txData"]').value
   const balance = this.props.balance
-  let message
 
   if (value.gt(balance)) {
     message = 'Insufficient funds.'
diff --git a/ui/app/util.js b/ui/app/util.js
index 3f8b4dcc3..293f4228c 100644
--- a/ui/app/util.js
+++ b/ui/app/util.js
@@ -193,6 +193,9 @@ function normalizeEthStringToWei (str) {
     while (decimal.length < 18) {
       decimal += '0'
     }
+    if (decimal.length > 18) {
+      decimal = decimal.slice(0, 18)
+    }
     const decimalBN = new ethUtil.BN(decimal, 10)
     eth = eth.add(decimalBN)
   }