Each time the UI's Handler Editor is invoked another status fetch thread is started

Description

Every time the UI's Handler Editor is invoked an additional status fetch started as follows

setTimeout(deployedAppsTicker, 2000);

And the prior repeating function(s) are all orphaned but still making HTTP requests.  Although Javascript is single threaded (such the same function running N times merely queues up) this can sometimes lead to odd behavior in the UI and aborted/canceled HTTP requests.  In addition is can create a lot of loading if a user session does a lot of edits.

To reproduce

You can see this behavior in Chrome by going to Eventing in the UI starting the developer tools and then select network and sub-select XHR then filter on the word "status" you will see a recurring request every 2 seconds.

Next just invoke a Function editor on any undeployed or deployed function via the UI's "Edit Javascript" button.

Video of issue

https://couchbase.zoom.us/rec/share/xdVNcejrrnlLQo3T62_iW6whErzOaaa8gyYZ86INzkxHBKQRG7wHruzoLb5ZkB-B

Possible fix (works for me - but there may be a better fix)

Make a global for the window above "function getAppStatus() {"

        window.g_tickerId = undefined;

Adjust the call to "setTimeout(deployedAppsTicker, 2000);" to set now set our new global.

        g_tickerId = setTimeout(deployedAppsTicker, 2000);

Search for the "Controller for editing handler code." and add

            // Stop recuring getAppStatus collection (and thus duplicate calls).    

            // avoids running multiple timers invoking getAppStatus            // (relies on a global context, window.g_tickerId)

            if (g_tickerId !== undefined) {

                clearTimeout(g_tickerId);

                g_tickerId = undefined;

            }

Of course it would be a better fix not to somehow get a different "context" in the first place when we hit the "Edit Javascript" button.