Estimate gas limit when the token amount changes. Fix amount input

ui/app/components/send_/send-content/send-amount-row/send-amount-row.component.js

@@ -23,6 +23,7 @@ export default class SendAmountRow extends Component {
     tokenBalance: PropTypes.string,
     updateSendAmount: PropTypes.func,
     updateSendAmountError: PropTypes.func,
+    updateGas: PropTypes.func,
   }
 
   validateAmount (amount) {
@@ -54,6 +55,15 @@ export default class SendAmountRow extends Component {
 
     setMaxModeTo(false)
     updateSendAmount(amount)
+    this.validateAmount(amount)
+  }
+
+  updateGas (amount) {
+    const { selectedToken, updateGas } = this.props
+
+    if (selectedToken) {
+      updateGas({ amount })
+    }
   }
 
   render () {
@@ -77,12 +87,12 @@ export default class SendAmountRow extends Component {
         <CurrencyDisplay
           conversionRate={amountConversionRate}
           convertedCurrency={convertedCurrency}
-          onBlur={newAmount => this.updateAmount(newAmount)}
-          onChange={newAmount => this.validateAmount(newAmount)}
+          onBlur={newAmount => this.updateGas(newAmount)}
+          onChange={newAmount => this.updateAmount(newAmount)}
           inError={inError}
           primaryCurrency={primaryCurrency || 'ETH'}
           selectedToken={selectedToken}
-          value={amount || '0x0'}
+          value={amount}
         />
       </SendRowWrapper>
     )

ui/app/components/send_/send-content/send-content.component.js

@@ -18,7 +18,7 @@ export default class SendContent extends Component {
         <div className="send-v2__form">
           <SendFromRow />
           <SendToRow updateGas={(updateData) => this.props.updateGas(updateData)} />
-          <SendAmountRow />
+          <SendAmountRow updateGas={(updateData) => this.props.updateGas(updateData)} />
           <SendGasRow />
         </div>
       </PageContainerContent>

ui/app/components/send_/send.component.js

@@ -38,7 +38,7 @@ export default class SendTransactionScreen extends PersistentForm {
     updateSendTokenBalance: PropTypes.func,
   };
 
-  updateGas ({ to } = {}) {
+  updateGas ({ to, amount: value } = {}) {
     const {
       amount,
       blockGasLimit,
@@ -60,7 +60,7 @@ export default class SendTransactionScreen extends PersistentForm {
       selectedAddress,
       selectedToken,
       to: to && to.toLowerCase(),
-      value: amount,
+      value: value || amount,
     })
   }
 

ui/app/components/send_/send.utils.js

@@ -203,21 +203,13 @@ async function estimateGas ({ selectedAddress, selectedToken, blockGasLimit, to,
           err.message.includes('gas required exceeds allowance or always failing transaction')
         )
         if (simulationFailed) {
-          const estimateWithBuffer = addGasBuffer(
-            paramsForGasEstimate.gas,
-            blockGasLimit,
-            selectedToken ? 2 : 1.5
-          )
+          const estimateWithBuffer = addGasBuffer(paramsForGasEstimate.gas, blockGasLimit, 1.5)
           return resolve(ethUtil.addHexPrefix(estimateWithBuffer))
         } else {
           return reject(err)
         }
       }
-      const estimateWithBuffer = addGasBuffer(
-        estimatedGas.toString(16),
-        blockGasLimit,
-        selectedToken ? 2 : 1.5
-      )
+      const estimateWithBuffer = addGasBuffer(estimatedGas.toString(16), blockGasLimit, 1.5)
       return resolve(ethUtil.addHexPrefix(estimateWithBuffer))
     })
   })