Fix memory leak from snapshot printing (#5279)

* Fix memory leak from obsolete snapshot printing

* Update issue number

* Rm "obsolete" to remove confusion

* Update index.js

Author: rickhanlonii

CHANGELOG.md

@@ -1,4 +1,9 @@
 ## master
+## jest 22.0.6
+
+### Fixes
+
+* `[jest-jasmine2]` Fix memory leak in snapshot reporting ([#5279](https://github.com/facebook/jest/pull/5279))
 
 ## jest 22.0.5
 

packages/jest-jasmine2/src/index.js

@@ -174,7 +174,8 @@ const addSnapshotData = (results, snapshotState) => {
   results.snapshot.unmatched = snapshotState.unmatched;
   results.snapshot.updated = snapshotState.updated;
   results.snapshot.unchecked = !status.deleted ? uncheckedCount : 0;
-  results.snapshot.uncheckedKeys = uncheckedKeys;
+  // Copy the array to prevent memory leaks
+  results.snapshot.uncheckedKeys = Array.from(uncheckedKeys);
 
   return results;
 };