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The "Q&A" Lesson is part of the full, JavaScript Performance course featured in this preview video. Here's what you'd learn in this lesson:

Steve answers questions from the audience.


Transcript from the "Q&A" Lesson

>> Steve Kinney: Question is, can you stack multiple cache control strategies in the header? My gut says no. I also realize that I have never attempted to. So I can't provide a really good answer, but my initial gut says I don't think you can.
>> Speaker 2: Someone test it.
>> Steve Kinney: Someone test it, keep recording.

>> Steve Kinney: Any other questions? Yeah.
>> Speaker 3: Maybe you don't know off the top of your head, but just curious, on either send grid or a previous project. Do you have a favorite sort of performance accomplishment or task you've made that comes to mind?
>> Steve Kinney: I think one of the most important ones, cuz it precedes all other ones, is getting the metrics in the first place.

Like figuring out the state of the world and being able to you know this, figuring out these actions, what are important action and figuring out how long they take and starting to set those. Either performance budget, right, if you don't want it to get worse, or performance goals.

That's a nontrivial task. Trying to get those measurements, cracking open the [INAUDIBLE] and getting all those numbers. It's the first step. It's usually stuff that doesn't exist in most applications. Patience, right? Like nobody's done it, thereby it's not a thing, right? Feels fine on my computer, [LAUGH] right?

Is the biggest thing. So like going ahead and using like the user timing API to like get some raw numbers, I think is really like the kind of like first. Cuz after that you can get the buy in around it, right? And like, Chrome has some interesting features now, that work different.

Like they don't work super well on my app because we have to log in, stuff like that but they actually show you your app versus your competitors. That's usually helpful for getting buy in. That's a relatively new one. There's another one in Chrome specifically, will show you code coverage, right?

Which means it'll load up all your code, you click around your app, and it'll show you lines of code that were never executed, right? And so like starting to get those metrics, starting to get like these, if I have like, let's make the app go faster! It's like great, everyone's like yeah!

And then nothing happens, right? Cuz like there's no like, here's the first thing to do, right? So I think that's the kind of most important part, right? Cuz like, once you kind of like build that into the culture that everyone kind of cares about, it becomes a lot easier to get all this stuff done.

And it's almost impossible to do before you build that. So it's kind of maybe not the answer you're looking for. But if you're asking what's the one I'm proudest of, like starting to implement those metrics and kind of getting the culture of performance in place.
>> Speaker 2: Thank you, that's great.

>> Steve Kinney: Anything else? Cool, thank you so much, everyone. [APPLAUSE]

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