feat: update Keepa and Stalker functionalities with enhanced price extraction logic and test cases

src/keepa.test.ts

@@ -48,7 +48,7 @@ test("lookupKeepaUpcs returns found, not_found, and multiple_asins outcomes", as
               current: [null, null, null, 1234],
               avg: [2500, null, null, 1400],
             },
-            csv: [[1, 2999]],
+            csv: [[5000000, 2999, 5000100]],
           },
           {
             asin: "B000MULTI01",
@@ -85,6 +85,7 @@ test("lookupKeepaUpcs returns found, not_found, and multiple_asins outcomes", as
   expect(details.get("012345678901")?.status).toBe("found");
   expect(details.get("012345678901")?.asin).toBe("B000FOUND01");
   expect(details.get("012345678901")?.keepaData?.currentPrice).toBe(29.99);
+  expect(details.get("012345678901")?.keepaData?.currentPrice).toBe(29.99);
 
   expect(details.get("098765432109")?.status).toBe("multiple_asins");
   expect(details.get("098765432109")?.candidateAsins).toEqual([

src/keepa.ts

@@ -529,14 +529,17 @@ function computeAmazonBuyBoxSharePctFromHistory(
   return Math.round((amazonMinutes / qualifiedMinutes) * 10_000) / 100;
 }
 
-function extractLatestPositivePrice(series: unknown): number | null {
-  if (!Array.isArray(series) || series.length < 2) return null;
-  const last = series[series.length - 1];
-  if (typeof last !== "number" || !Number.isFinite(last) || last <= 0) {
-    return null;
-  }
-  return last / 100;
-}
+function extractLatestPositivePrice(series: unknown): number | null {
+  if (!Array.isArray(series) || series.length < 2) return null;
+  for (let i = series.length - 1; i >= 1; i--) {
+    if (i % 2 === 0) continue;
+    const value = series[i];
+    if (typeof value === "number" && Number.isFinite(value) && value > 0) {
+      return value / 100;
+    }
+  }
+  return null;
+}
 
 function pickKeepaNumber(...values: unknown[]): number | null {
   for (const value of values) {
@@ -548,16 +551,14 @@ function pickKeepaNumber(...values: unknown[]): number | null {
   return null;
 }
 
-function extractCurrentPrice(csv: number[][] | undefined): number | null {
-  if (!csv) return null;
-
-  // csv[0] = Amazon price history, csv[1] = Marketplace new price history
-  // Each is [time, price, time, price, ...] — last value is most recent
-  for (const series of [csv[0], csv[1]]) {
-    if (series && series.length >= 2) {
-      const lastPrice = series[series.length - 1]!;
-      if (lastPrice > 0) return lastPrice / 100;
-    }
-  }
-  return null;
-}
+function extractCurrentPrice(csv: number[][] | undefined): number | null {
+  if (!csv) return null;
+
+  // csv[0] = Amazon price history, csv[1] = Marketplace new price history
+  // Each is [time, price, time, price, ...]. Only odd indexes are prices.
+  for (const series of [csv[0], csv[1]]) {
+    const latestPrice = extractLatestPositivePrice(series);
+    if (latestPrice != null) return latestPrice;
+  }
+  return null;
+}

src/stalker-sellability.test.ts

@@ -89,7 +89,7 @@ test("sellability checks matched seller inventory, not the source ASIN", async (
                   current: [null, null, null, 12345, null, null, null, null, null, null, null, 7],
                   avg: [2500],
                 },
-                csv: [[0, 1999]],
+                csv: [[5000000, 1999, 5000100]],
               },
             ],
             tokensLeft: 10,

src/stalker.ts

@@ -1355,7 +1355,11 @@ function extractCurrentPrice(csv: unknown): number | null {
 
 function extractLatestPositiveKeepaPrice(history: unknown): number | null {
   if (!Array.isArray(history)) return null;
-  for (let i = history.length - 1; i >= 0; i--) {
+
+  // Keepa CSV histories are [time, value, time, value, ...]. Only odd indexes
+  // are prices; even indexes are Keepa timestamps and can look like huge prices.
+  for (let i = history.length - 1; i >= 1; i--) {
+    if (i % 2 === 0) continue;
     const value = extractNumber(history[i]);
     if (value != null && value > 0) return value / 100;
   }