fix(collection): preserve maps for non-finite upper bounds

steipete · steipete · commit 6e25112aad71 · 2026-05-28T22:42:43.000-04:00
diff --git a/src/infra/map-size.test.ts b/src/infra/map-size.test.ts
@@ -34,6 +34,39 @@ describe("pruneMapToMaxSize", () => {
       maxSize: -4,
       expected: [],
     },
+    {
+      name: "leaves maps untouched for NaN limits",
+      entries: [
+        ["a", 1],
+        ["b", 2],
+      ] as const,
+      maxSize: Number.NaN,
+      expected: [
+        ["a", 1],
+        ["b", 2],
+      ],
+    },
+    {
+      name: "leaves maps untouched for positive infinity limits",
+      entries: [
+        ["a", 1],
+        ["b", 2],
+      ] as const,
+      maxSize: Number.POSITIVE_INFINITY,
+      expected: [
+        ["a", 1],
+        ["b", 2],
+      ],
+    },
+    {
+      name: "clears maps for negative infinity limits",
+      entries: [
+        ["a", 1],
+        ["b", 2],
+      ] as const,
+      maxSize: Number.NEGATIVE_INFINITY,
+      expected: [],
+    },
     {
       name: "leaves undersized maps untouched",
       entries: [["a", 1]] as const,
diff --git a/src/infra/map-size.ts b/src/infra/map-size.ts
@@ -1,4 +1,7 @@
 export function pruneMapToMaxSize<K, V>(map: Map<K, V>, maxSize: number): void {
+  if (Number.isNaN(maxSize) || maxSize === Number.POSITIVE_INFINITY) {
+    return;
+  }
   const limit = Math.max(0, Math.floor(maxSize));
   if (limit <= 0) {
     map.clear();
