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The cost of parsing JSON

v8.dev

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Re: The cost of parsing JSON

#21

Post by Trufa »

cryptica wrote: post #18

This is a terrible idea. 2x best-case performance is nothing. Especially not worth the extra hassle and complexity that it adds to the code. The sad thing about these kinds of articles is that there are people out there who will read this and actually start implementing it in their code.

What's the damage in knowing? I would say it falls under, good to know but be very careful. 2x performance is definitely not nothing if your corner case happens to benefit from this, if you prematurely optimize, that's on you.

Re: The cost of parsing JSON

#24

Post by pier25 »

ijpoijpoihpiuoh wrote: post #2

Title correction: it's faster to parse and initialize using JSON than to parse and compile the code required to initialize Objects directly. If the code is already compiled, it's much faster to initialize in code. At least that's my understanding of the linked article.

Is there a way to provide v8 with compiled code instead of unparsed JS?

Re: The cost of parsing JSON

#25

Post by no_gravity » 

    Because the JSON grammar is much simpler than
    JavaScript’s grammar, JSON can be parsed more
    efficiently than JavaScript.
Hmm.. shouldn't that hold for most programming languages then?

Let's try it for PHP:

    time php -r 'for ($i=0;$i
So for 10 million repetitions, a small PHP structure is about 20x faster then parsing JSON. But to test the point of the article, one should use the sama data structure it uses (https://raw.githubusercontent.com/WebKit/webkit/ffdd2799d323...) and parse it only once.

Re: The cost of parsing JSON

#26

Post by eloff »

cryptica wrote: post #18

This is a terrible idea. 2x best-case performance is nothing. Especially not worth the extra hassle and complexity that it adds to the code. The sad thing about these kinds of articles is that there are people out there who will read this and actually start implementing it in their code.

JSON.parse is complexity? Just separating your data from your code alone is worth it for the architectural benefits, this would be a net improvement to code quality. Performance matters, if you have a lot of data like this that can also be a big win.

Re: The cost of parsing JSON

#27

Post by harimau777 »

jakelazaroff wrote: post #9
ijpoijpoihpiuoh wrote: post #2

Title correction: it's faster to parse and initialize using JSON than to parse and compile the code required to initialize Objects directly. If the code is already compiled, it's much faster to initialize in code. At least that's my understanding of the linked article.

I think your understanding is correct. The relevant quote: > As long as the JSON string is only evaluated once, the JSON.parse approach is much faster compared to the JavaScript object literal, especially for cold loads.

So that means that theoretically someone could write a Babel plugin that replaces objects with some sort of memoized JSON.parse in order to get the best of both worlds? Could that actually work in practice?

Edit: I think you would also need to identify and only optimize objects that are handled immutably. However, my understanding is that you can do that in a compiler/transpiler fairly easily.

Re: The cost of parsing JSON

#29

Post by Supermancho »

cryptica wrote: post #18

This is a terrible idea. 2x best-case performance is nothing. Especially not worth the extra hassle and complexity that it adds to the code. The sad thing about these kinds of articles is that there are people out there who will read this and actually start implementing it in their code.

> This is a terrible idea

It's not just an idea, it's engineering with analysis. Smack on a pre-processor to wrap your cold start configurations (if they are large) and you'll get a performance boost, is the takeaway.

> 2x best-case performance is nothing

I'm not sure how you can say that with a straight face. Altering the bootup time of many systems by a factor is non-trivial.

Re: The cost of parsing JSON

#30

Post by eloff »

no_gravity wrote: post #25

Because the JSON grammar is much simpler than JavaScript’s grammar, JSON can be parsed more efficiently than JavaScript. Hmm.. shouldn't that hold for most programming languages then? Let's try it for PHP: time php -r 'for ($i=0;$i So for 10 million repetitions, a small PHP structure is about 20x faster then parsing JSON. But to test the point of the article, one should use the sama data structure it uses ( https://r…

This completely depends on the implementation of JSON in your language. That happens to be heavily optimized in JavaScript for obvious reasons.
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