undocumented console.timeEnd() change in 6.x

[ben-page]

• Version: v6.0.0
• Platform: Windows 10 x64
• Subsystem: console

_Description_
On node < 6 you could call timeEnd() multiple times for the same label to receive the current elapsed time. This no longer works in node v6.

This is a side effect of this pull request #3562, which fixed timers being leaked. This change completely makes sense, but it also removes (probably unintended) functionality. Should this change be in the documentation?

_Example_

console.time('timer');
setTimeout(function() {
    console.timeEnd('timer');
}, 10);
setTimeout(function() {
    console.timeEnd('timer');
}, 20);

output on node v5.9.1

timer: 11.898ms
timer: 20.454ms

output on node v6.0.0

timer: 11.111ms
(node:33232) Warning: No such label 'timer' for console.timeEnd()

[cjihrig]

Care to open a documentation PR?

[whitlockjc]

I agree it should be documented even though the way things worked prior to v6.0.0 was by accident. If @ben-page doesn't want to do the PR, I will.

Assigning to myself.

[ben-page]

I'd be happy to. I'm not certain of the appropriate format for documenting API changes. Is there an example in the docs you could point me to?

[whitlockjc]

This is a really good read: https://github.com/nodejs/node/blob/master/CONTRIBUTING.md Make sure you look at the suggested Git commit log message. Also, here is a randomly picked doc commit that made it through the review process: 31de5cc Please let us know if we can clear anything else up or if you need assistance.

[jasnell]

Fix landed in #6454