From fc0af50ab57bc1f5d04977cf1b2e17cf2c953433 Mon Sep 17 00:00:00 2001
From: Mononaut <github@monospace.live>
Date: Thu, 19 Jan 2023 11:09:03 -0600
Subject: [PATCH] Fix bugged mempool block gradients

---
 backend/src/api/common.ts | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/backend/src/api/common.ts b/backend/src/api/common.ts
index f0c5c6b88..29dad1a5d 100644
--- a/backend/src/api/common.ts
+++ b/backend/src/api/common.ts
@@ -35,16 +35,25 @@ export class Common {
   }
 
   static getFeesInRange(transactions: TransactionExtended[], rangeLength: number) {
-    const arr = [transactions[transactions.length - 1].effectiveFeePerVsize];
+    const filtered: TransactionExtended[] = [];
+    let lastValidRate = Infinity;
+    // filter out anomalous fee rates to ensure monotonic range
+    for (const tx of transactions) {
+      if (tx.effectiveFeePerVsize <= lastValidRate) {
+        filtered.push(tx);
+        lastValidRate = tx.effectiveFeePerVsize;
+      }
+    }
+    const arr = [filtered[filtered.length - 1].effectiveFeePerVsize];
     const chunk = 1 / (rangeLength - 1);
     let itemsToAdd = rangeLength - 2;
 
     while (itemsToAdd > 0) {
-      arr.push(transactions[Math.floor(transactions.length * chunk * itemsToAdd)].effectiveFeePerVsize);
+      arr.push(filtered[Math.floor(filtered.length * chunk * itemsToAdd)].effectiveFeePerVsize);
       itemsToAdd--;
     }
 
-    arr.push(transactions[0].effectiveFeePerVsize);
+    arr.push(filtered[0].effectiveFeePerVsize);
     return arr;
   }