Correct remainingTTL reported on status object

Fix: #293 Sometimes basic addition and subtraction is really hard.
isaacs · Apr 23, 2023 · 3a71a30 · 3a71a30
1 parent 4134a83
commit 3a71a30
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Showing 2 changed files with 51 additions and 46 deletions.
diff --git a/src/index.ts b/src/index.ts
@@ -1167,7 +1167,8 @@ export class LRUCache<K extends {}, V extends {}, FC = unknown> {
         status.ttl = ttl
         status.start = start
         status.now = cachedNow || getNow()
-        status.remainingTTL = status.now + ttl - start
+        const age = status.now - start
+        status.remainingTTL = ttl - age
       }
     }
 
@@ -1197,9 +1198,13 @@ export class LRUCache<K extends {}, V extends {}, FC = unknown> {
       if (index === undefined) {
         return 0
       }
-      return ttls[index] === 0 || starts[index] === 0
-        ? Infinity
-        : starts[index] + ttls[index] - (cachedNow || getNow())
+      const ttl = ttls[index]
+      const start = starts[index]
+      if (ttl === 0 || start === 0) {
+        return Infinity
+      }
+      const age = (cachedNow || getNow()) - start
+      return ttl - age
     }
 
     this.#isStale = index => {

diff --git a/tap-snapshots/test/ttl.ts.test.cjs b/tap-snapshots/test/ttl.ts.test.cjs
@@ -45,28 +45,28 @@ Array [
   Object {
     "get": "hit",
     "now": 1969,
-    "remainingTTL": 15,
+    "remainingTTL": 5,
     "start": 1964,
     "ttl": 10,
   },
   Object {
     "get": "hit",
     "now": 1974,
-    "remainingTTL": 20,
+    "remainingTTL": 0,
     "start": 1964,
     "ttl": 10,
   },
   Object {
     "has": "stale",
     "now": 1975,
-    "remainingTTL": 21,
+    "remainingTTL": -1,
     "start": 1964,
     "ttl": 10,
   },
   Object {
     "get": "stale",
     "now": 1975,
-    "remainingTTL": 21,
+    "remainingTTL": -1,
     "start": 1964,
     "ttl": 10,
   },
@@ -80,28 +80,28 @@ Array [
   Object {
     "has": "hit",
     "now": 2025,
-    "remainingTTL": 150,
+    "remainingTTL": 50,
     "start": 1975,
     "ttl": 100,
   },
   Object {
     "get": "hit",
     "now": 2025,
-    "remainingTTL": 150,
+    "remainingTTL": 50,
     "start": 1975,
     "ttl": 100,
   },
   Object {
     "has": "stale",
     "now": 2076,
-    "remainingTTL": 201,
+    "remainingTTL": -1,
     "start": 1975,
     "ttl": 100,
   },
   Object {
     "get": "stale",
     "now": 2076,
-    "remainingTTL": 201,
+    "remainingTTL": -1,
     "start": 1975,
     "ttl": 100,
   },
@@ -171,14 +171,14 @@ Array [
   Object {
     "has": "stale",
     "now": 2087,
-    "remainingTTL": 21,
+    "remainingTTL": -1,
     "start": 2076,
     "ttl": 10,
   },
   Object {
     "get": "stale",
     "now": 2087,
-    "remainingTTL": 21,
+    "remainingTTL": -1,
     "start": 2076,
     "ttl": 10,
   },
@@ -204,49 +204,49 @@ Array [
   Object {
     "get": "hit",
     "now": 1522,
-    "remainingTTL": 15,
+    "remainingTTL": 5,
     "start": 1517,
     "ttl": 10,
   },
   Object {
     "get": "hit",
     "now": 1527,
-    "remainingTTL": 20,
+    "remainingTTL": 0,
     "start": 1517,
     "ttl": 10,
   },
   Object {
     "has": "stale",
     "now": 1529,
-    "remainingTTL": 22,
+    "remainingTTL": -2,
     "start": 1517,
     "ttl": 10,
   },
   Object {
     "get": "stale",
     "now": 1529,
-    "remainingTTL": 22,
+    "remainingTTL": -2,
     "start": 1517,
     "ttl": 10,
   },
   Object {
     "has": "hit",
     "now": 1579,
-    "remainingTTL": 150,
+    "remainingTTL": 50,
     "start": 1529,
     "ttl": 100,
   },
   Object {
     "get": "hit",
     "now": 1579,
-    "remainingTTL": 150,
+    "remainingTTL": 50,
     "start": 1529,
     "ttl": 100,
   },
   Object {
     "get": "stale",
     "now": 1630,
-    "remainingTTL": 201,
+    "remainingTTL": -1,
     "start": 1529,
     "ttl": 100,
   },
@@ -316,14 +316,14 @@ Array [
   Object {
     "has": "stale",
     "now": 1641,
-    "remainingTTL": 21,
+    "remainingTTL": -1,
     "start": 1630,
     "ttl": 10,
   },
   Object {
     "get": "stale",
     "now": 1641,
-    "remainingTTL": 21,
+    "remainingTTL": -1,
     "start": 1630,
     "ttl": 10,
   },
@@ -383,14 +383,14 @@ Array [
   Object {
     "has": "stale",
     "now": 1952,
-    "remainingTTL": 121,
+    "remainingTTL": -101,
     "start": 1841,
     "ttl": 10,
   },
   Object {
     "get": "stale",
     "now": 1952,
-    "remainingTTL": 121,
+    "remainingTTL": -101,
     "start": 1841,
     "ttl": 10,
   },
@@ -464,28 +464,28 @@ Array [
   Object {
     "get": "hit",
     "now": 453,
-    "remainingTTL": 15,
+    "remainingTTL": 5,
     "start": 448,
     "ttl": 10,
   },
   Object {
     "get": "hit",
     "now": 458,
-    "remainingTTL": 20,
+    "remainingTTL": 0,
     "start": 448,
     "ttl": 10,
   },
   Object {
     "has": "stale",
     "now": 459,
-    "remainingTTL": 21,
+    "remainingTTL": -1,
     "start": 448,
     "ttl": 10,
   },
   Object {
     "get": "stale",
     "now": 459,
-    "remainingTTL": 21,
+    "remainingTTL": -1,
     "start": 448,
     "ttl": 10,
   },
@@ -499,28 +499,28 @@ Array [
   Object {
     "has": "hit",
     "now": 509,
-    "remainingTTL": 150,
+    "remainingTTL": 50,
     "start": 459,
     "ttl": 100,
   },
   Object {
     "get": "hit",
     "now": 509,
-    "remainingTTL": 150,
+    "remainingTTL": 50,
     "start": 459,
     "ttl": 100,
   },
   Object {
     "has": "stale",
     "now": 560,
-    "remainingTTL": 201,
+    "remainingTTL": -1,
     "start": 459,
     "ttl": 100,
   },
   Object {
     "get": "stale",
     "now": 560,
-    "remainingTTL": 201,
+    "remainingTTL": -1,
     "start": 459,
     "ttl": 100,
   },
@@ -590,14 +590,14 @@ Array [
   Object {
     "has": "stale",
     "now": 571,
-    "remainingTTL": 21,
+    "remainingTTL": -1,
     "start": 560,
     "ttl": 10,
   },
   Object {
     "get": "stale",
     "now": 571,
-    "remainingTTL": 21,
+    "remainingTTL": -1,
     "start": 560,
     "ttl": 10,
   },
@@ -623,49 +623,49 @@ Array [
   Object {
     "get": "hit",
     "now": 6,
-    "remainingTTL": 15,
+    "remainingTTL": 5,
     "start": 1,
     "ttl": 10,
   },
   Object {
     "get": "hit",
     "now": 11,
-    "remainingTTL": 20,
+    "remainingTTL": 0,
     "start": 1,
     "ttl": 10,
   },
   Object {
     "has": "stale",
     "now": 13,
-    "remainingTTL": 22,
+    "remainingTTL": -2,
     "start": 1,
     "ttl": 10,
   },
   Object {
     "get": "stale",
     "now": 13,
-    "remainingTTL": 22,
+    "remainingTTL": -2,
     "start": 1,
     "ttl": 10,
   },
   Object {
     "has": "hit",
     "now": 63,
-    "remainingTTL": 150,
+    "remainingTTL": 50,
     "start": 13,
     "ttl": 100,
   },
   Object {
     "get": "hit",
     "now": 63,
-    "remainingTTL": 150,
+    "remainingTTL": 50,
     "start": 13,
     "ttl": 100,
   },
   Object {
     "get": "stale",
     "now": 114,
-    "remainingTTL": 201,
+    "remainingTTL": -1,
     "start": 13,
     "ttl": 100,
   },
@@ -735,14 +735,14 @@ Array [
   Object {
     "has": "stale",
     "now": 125,
-    "remainingTTL": 21,
+    "remainingTTL": -1,
     "start": 114,
     "ttl": 10,
   },
   Object {
     "get": "stale",
     "now": 125,
-    "remainingTTL": 21,
+    "remainingTTL": -1,
     "start": 114,
     "ttl": 10,
   },
@@ -802,14 +802,14 @@ Array [
   Object {
     "has": "stale",
     "now": 436,
-    "remainingTTL": 121,
+    "remainingTTL": -101,
     "start": 325,
     "ttl": 10,
   },
   Object {
     "get": "stale",
     "now": 436,
-    "remainingTTL": 121,
+    "remainingTTL": -101,
     "start": 325,
     "ttl": 10,
   },