[PerformanceTimeline] API/WebIDL related feedback (was: Unclear what getEntries and company return)

Le 22/08/2013 20:37, James Simonsen a écrit :
> On Wed, Aug 21, 2013 at 7:41 PM, Boris Zbarsky <bzbarsky@mit.edu 
> <mailto:bzbarsky@mit.edu>> wrote:
>
>     This ambiguity seems like a hard blocker to actually proceeding
>     with our implementation.
>
>     2)  It's not quite clear to me what the "contains a copy" language
>     means.  Does this mean that this predicate:
>
>       performance.getEntries()[0] == performance.getEntries()[0]
>
>     tests false if getEntries returns a nonempty list?  That is, each
>     time the list is returned it has to contain brand-new objects?  If
>     this is in fact the intent, it's rather surprising; given that the
>     objects only have readonly properties it seems like it would be
>     better to return existing objects.  If we _do_ want to return
>     brand-new objects every time, it seems like we should simply
>     return dictionaries instead: then we get the new-object behavior
>     for free and script gets non-magical objects to work with.
>
>
> Blink doesn't create copies. It'd be silly to. I think we should just 
> update the spec.
Maybe it should just be .entries, then (instead of .getEntries() )?

I'm not sure I quite understand the difference between entryType and name.

I'm not sure I see the benefit of the getEntriesByType and 
getEntriesByName methods since what they do can be done very easily in JS:

   var fooEntries = performance.entries.filter(function(e){return e.name 
=== "foo"}) // ES5
   var fooEntries = performance.entries.filter(e => e.name === "foo") // ES6


Also, let's show good practices in our examples so that devs learn how 
to write better JS:

     function measurePerf(){
         if(window.console){
             performance.entries.forEach(function(e){
                 console.group('perf entry '+ e.name);
                 console.log('Entry Type:', e.entryType);
                 console.log('Start Time:', e.startTime);
                 console.log('Duration:', e.duration);
                 console.groupEnd();
             })
         }
     }

Thanks,

David