From 7dd78ef5f334655d531b3b7c8e4c68f138292ff9 Mon Sep 17 00:00:00 2001
From: michael1011 <me@michael1011.at>
Date: Sat, 11 Jan 2025 21:27:27 +0100
Subject: [PATCH] fix: round max routing to 4 decimal places (#778)

---
 lib/Utils.ts                               |  3 +++
 lib/rates/providers/RateProviderTaproot.ts | 12 ++++++++----
 test/unit/Utils.spec.ts                    | 10 ++++++++++
 3 files changed, 21 insertions(+), 4 deletions(-)

diff --git a/lib/Utils.ts b/lib/Utils.ts
index 42e888a6..881d5fdf 100644
--- a/lib/Utils.ts
+++ b/lib/Utils.ts
@@ -639,3 +639,6 @@ export const arrayToChunks = <T>(array: T[], chunkSize: number): T[][] => {
 };
 
 export const bigIntMax = (a: bigint, b: bigint) => (a > b ? a : b);
+
+export const roundToDecimals = (value: number, decimals: number): number =>
+  Number(value.toFixed(decimals));
diff --git a/lib/rates/providers/RateProviderTaproot.ts b/lib/rates/providers/RateProviderTaproot.ts
index b524cf92..05554240 100644
--- a/lib/rates/providers/RateProviderTaproot.ts
+++ b/lib/rates/providers/RateProviderTaproot.ts
@@ -6,6 +6,7 @@ import {
   getSendingChain,
   hashString,
   mapToObject,
+  roundToDecimals,
   splitPairId,
 } from '../../Utils';
 import {
@@ -543,14 +544,17 @@ class RateProviderTaproot extends RateProviderBase<SwapTypes> {
 
               if (maxRoutingFeeOverride !== undefined) {
                 (result as SubmarinePairTypeTaproot).fees.maximalRoutingFee =
-                  maxRoutingFeeOverride * 100;
+                  roundToDecimals(maxRoutingFeeOverride * 100, 4);
               } else {
                 const currency = this.currencies.get(to);
 
                 (result as SubmarinePairTypeTaproot).fees.maximalRoutingFee =
-                  (currency?.lndClient?.maxPaymentFeeRatio ||
-                    currency?.clnClient?.maxPaymentFeeRatio ||
-                    0) * 100;
+                  roundToDecimals(
+                    (currency?.lndClient?.maxPaymentFeeRatio ||
+                      currency?.clnClient?.maxPaymentFeeRatio ||
+                      0) * 100,
+                    4,
+                  );
               }
             }
 
diff --git a/test/unit/Utils.spec.ts b/test/unit/Utils.spec.ts
index 80fb9f9c..1bd8360e 100644
--- a/test/unit/Utils.spec.ts
+++ b/test/unit/Utils.spec.ts
@@ -456,4 +456,14 @@ describe('Utils', () => {
   `('should get maximal bigint', ({ a, b, expected }) => {
     expect(bigIntMax(a, b)).toEqual(expected);
   });
+
+  test.each`
+    value         | decimals | expected
+    ${1.23456789} | ${2}     | ${1.23}
+    ${1.23456789} | ${4}     | ${1.2346}
+    ${0.35001}    | ${4}     | ${0.35}
+    ${0.3500999}  | ${4}     | ${0.3501}
+  `('should round to decimals', ({ value, decimals, expected }) => {
+    expect(utils.roundToDecimals(value, decimals)).toEqual(expected);
+  });
 });