should switch first snap correctly

Author: enisdenjo

internal/perf/src/heapsnapshot.ts

@@ -41,6 +41,9 @@ export async function leakingObjectsInHeapSnapshotFiles(
     const aggregates = baseSnap.aggregatesForDiff(defs);
     const snapshotDiff = snap.calculateSnapshotDiff('', aggregates);
 
+    // next base snap is this/current snap
+    baseSnap = snap;
+
     const growingDiff: HeapSnapshotDiff = {};
     for (const { addedIndexes, deletedIndexes, ...diff } of Object.values(
       snapshotDiff,
@@ -81,8 +84,6 @@ export async function leakingObjectsInHeapSnapshotFiles(
         delete totalGrowingDiff[totalDiffName];
       }
     }
-
-    baseSnap = snap;
   }
 
   return totalGrowingDiff;

internal/perf/tests/heapsnapshot.test.ts

@@ -51,13 +51,13 @@ it.skipIf(
       .toMatchInlineSnapshot(`
       {
         "(compiled code)": {
-          "addedCount": 24267,
-          "addedSize": 4981944,
-          "countDelta": -19747,
+          "addedCount": 16020,
+          "addedSize": 3015968,
+          "countDelta": -9728,
           "name": "(compiled code)",
-          "removedCount": 44014,
-          "removedSize": 2541944,
-          "sizeDelta": 2440000,
+          "removedCount": 25748,
+          "removedSize": 1731144,
+          "sizeDelta": 1284824,
         },
       }
     `);