fix: calculation of amount to approve

QuickSwap · Jul 13, 2023 · 0e7869b · 0e7869b
1 parent e0b49e7
commit 0e7869b
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Showing 2 changed files with 41 additions and 36 deletions.
diff --git a/src/components/Swap/SwapBestTrade.tsx b/src/components/Swap/SwapBestTrade.tsx
@@ -379,6 +379,11 @@ const SwapBestTrade: React.FC<{
     inputCurrencyV3,
     outputCurrencyV3,
   ]);
+
+  const maxAmountInputV2 = maxAmountSpend(
+    chainIdToUse,
+    currencyBalances[Field.INPUT],
+  );
   const formattedAmounts = useMemo(() => {
     return {
       [independentField]: typedValue,
@@ -388,11 +393,40 @@ const SwapBestTrade: React.FC<{
     };
   }, [independentField, typedValue, dependentField, showWrap, parsedAmounts]);
 
+  const maxAmountInput =
+    maxAmountInputV2 && inputCurrencyV3
+      ? CurrencyAmount.fromRawAmount(inputCurrencyV3, maxAmountInputV2.raw)
+      : undefined;
+
+  const handleMaxInput = useCallback(() => {
+    maxAmountInput && onUserInput(Field.INPUT, maxAmountInput.toExact());
+    setSwapType(SwapSide.SELL);
+  }, [maxAmountInput, onUserInput]);
+
+  const handleHalfInput = useCallback(() => {
+    if (!maxAmountInput) {
+      return;
+    }
+
+    const halvedAmount = maxAmountInput.divide('2');
+
+    onUserInput(
+      Field.INPUT,
+      halvedAmount.toFixed(maxAmountInput.currency.decimals),
+    );
+    setSwapType(SwapSide.SELL);
+  }, [maxAmountInput, onUserInput]);
+
+  const atMaxAmountInput = Boolean(
+    maxAmountInput && parsedAmounts[Field.INPUT]?.equalTo(maxAmountInput),
+  );
+
   const [approval, approveCallback] = useApproveCallbackFromBestTrade(
     pct,
     inputCurrencyV3,
     optimalRate,
     bonusRouteFound,
+    atMaxAmountInput,
   );
 
   const showApproveFlow =
@@ -620,38 +654,6 @@ const SwapBestTrade: React.FC<{
     [onUserInput],
   );
 
-  const maxAmountInputV2 = maxAmountSpend(
-    chainIdToUse,
-    currencyBalances[Field.INPUT],
-  );
-  const maxAmountInput =
-    maxAmountInputV2 && inputCurrencyV3
-      ? CurrencyAmount.fromRawAmount(inputCurrencyV3, maxAmountInputV2.raw)
-      : undefined;
-
-  const handleMaxInput = useCallback(() => {
-    maxAmountInput && onUserInput(Field.INPUT, maxAmountInput.toExact());
-    setSwapType(SwapSide.SELL);
-  }, [maxAmountInput, onUserInput]);
-
-  const handleHalfInput = useCallback(() => {
-    if (!maxAmountInput) {
-      return;
-    }
-
-    const halvedAmount = maxAmountInput.divide('2');
-
-    onUserInput(
-      Field.INPUT,
-      halvedAmount.toFixed(maxAmountInput.currency.decimals),
-    );
-    setSwapType(SwapSide.SELL);
-  }, [maxAmountInput, onUserInput]);
-
-  const atMaxAmountInput = Boolean(
-    maxAmountInput && parsedAmounts[Field.INPUT]?.equalTo(maxAmountInput),
-  );
-
   const onParaswap = () => {
     if (showWrap && onWrap) {
       onWrap();
@@ -895,7 +897,6 @@ const SwapBestTrade: React.FC<{
     typedValue,
     approval, //Added to trigger bonus route search when approval changes
   ]);
-
   //Reset approvalSubmitted when approval changes, it's needed when user hadn't nor paraswap neither wallchain approvals
   useEffect(() => {
     if (

diff --git a/src/hooks/useApproveCallback.ts b/src/hooks/useApproveCallback.ts
@@ -291,15 +291,19 @@ export function useApproveCallbackFromBestTrade(
   currency?: Currency,
   optimalRate?: OptimalRate,
   bonusRouteFound?: boolean,
+  atMaxAmountInput?: boolean,
 ): [ApprovalState, () => Promise<void>] {
   const { chainId } = useActiveWeb3React();
   const amountToApprove = useMemo(
     () =>
       optimalRate
-        ? new Fraction(ONE).add(allowedSlippage).multiply(optimalRate.srcAmount)
-            .quotient
+        ? atMaxAmountInput
+          ? new Fraction(ONE).multiply(optimalRate.srcAmount).quotient
+          : new Fraction(ONE)
+              .add(allowedSlippage)
+              .multiply(optimalRate.srcAmount).quotient
         : undefined,
-    [optimalRate, allowedSlippage],
+    [optimalRate, allowedSlippage, atMaxAmountInput],
   );
 
   return useApproveCallbackV3(