Created attachment 282338 [details] Test case If we log object right before deleting one of its properties a wrong version appears in the console. Example: var test = {}; test.foo = {}; test.foo.bar = "Lorem ipsum"; console.log(test); delete test.foo.bar; Logged object doesn't have "bar" property when using: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.21 (KHTML, like Gecko) rekonq/2.3.2 Safari/537.21 In the past we already had some problem with displaying objects with console.log (#35801) it looks like similar issue (does it help to find a solution?).
<rdar://problem/27097304>
This is expected behavior. When Web Inspector is open, it provides a preview/snapshot of what the object was that was logged in case the object changes. For large objects, when expanded, you see the live, current data. But for simple objects, when logged, we provide the snapshots. In this particular case, you logged a simple JSON stringifyable object, and the console message includes the complete description of the object at the time it was logged. That would be what I expect. Is this causing you an issue in some more realistic situation?
To expand on my last comment. When Web Inspector is closed, it does not do this previewing/snapshotting behavior. The performance overhead of console methods is a minimum when Web Inspector is closed.