

Fun with Javascript and function tracing. - ebobby
http://ebobby.org/2013/05/18/Fun-with-Javascript-and-function-tracing.html

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modeless
At Google we built a tool for this that presents the results graphically on a
timeline: <http://google.github.io/tracing-framework/>

It's been invaluable for us on Maps to be able to graphically trace the
execution of our code.

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ebobby
You guys definitely have more time for that than I do :)

When I started doing this I had a lot of ideas, even sample profiling, etc,
etc. But realized that in order to make it actually useful and being able to
trace everything without slowing the crap down of everything I would had to do
some sort of plugin or module, ala Firebug. Not a weekend project anymore.

But apparently you guys already did it! very cool. I'll check it out.

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mAritz
There is also the nifty "Break on ... Attributes modification" in the web
inspector.

Just go to the element in the "Elements" tab, right-click, "Break on ..." and
choose what kind of breakpoint you want.

I just tested it with jQuery.hide() and it works wonderfully.

~~~
nilliams
Thanks for this, did not know that could be done.

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Dru89
I love this. Will probably add a bookmarklet or something to load it and use
it when debugging.

My only question is how it works with prototyped or nested functions, such as
the `hide` method that you mentioned. Would you just call
Tracing.trace('$.fn.hide', 'Object.static_method',
'Object.prototype.object_method') for example to get access to those
particular methods?

~~~
ebobby
Yes, exactly. So far it can only access functions that it can traverse
directly by name when passed the name as a string as you suggested.

Local functions as in nested inside another function, or directly assigned to
a local variable, or passed as a function argument the lib cannot hook into
because there is no way I can address them since I am not in your lexical
context and if you pass them to the library you pass only the reference to the
function, not a reference to the reference.

In that case I guess it may be possible for the library to hook your code into
them only if you pass them to the library and the library returns a new
function for you but that is a little too cumbersome.

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ezraroi
Nice one. Looks very useful, will try it for sure

