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How JavaScript works: the rendering engine and tips to optimize its performance

blog.sessionstack.com

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Re: How JavaScript works: the rendering engine and tips to optimize its performance

#4

Post by Klathmon »

This is somewhat off-topic, but has anyone here used SessionStack?

How well does the service work, and is there a noticeable performance impact for the software to record on mid-range mobile devices?

It looks really interesting and would probably be really helpful, but I can't include anything else in our applications that will further tax our already struggling lower-end devices with more code that needs to run and more data that needs to be transmitted.

Re: How JavaScript works: the rendering engine and tips to optimize its performance

#5

Post by zlatkov »

Klathmon wrote: post #4

This is somewhat off-topic, but has anyone here used SessionStack? How well does the service work, and is there a noticeable performance impact for the software to record on mid-range mobile devices? It looks really interesting and would probably be really helpful, but I can't include anything else in our applications that will further tax our already struggling lower-end devices with more code that needs to run and…

Co-founder of SessionStack here :) I'd be happy to show you a personal demo, explain how SessionStack works and explain why it won't impact the performance of your product. Can you ping me at alex@sessionstack.com?

Re: How JavaScript works: the rendering engine and tips to optimize its performance

#6

Post by Klathmon »

zlatkov wrote: post #5
Klathmon wrote: post #4

This is somewhat off-topic, but has anyone here used SessionStack? How well does the service work, and is there a noticeable performance impact for the software to record on mid-range mobile devices? It looks really interesting and would probably be really helpful, but I can't include anything else in our applications that will further tax our already struggling lower-end devices with more code that needs to run and…

Co-founder of SessionStack here :) I'd be happy to show you a personal demo, explain how SessionStack works and explain why it won't impact the performance of your product. Can you ping me at alex@sessionstack.com?

Will do, and I was planning on trying out the service at some point (we use Sentry and discovered you through their integrations page), but I figured I'd take this chance to see what kind of experience others are having.

Re: How JavaScript works: the rendering engine and tips to optimize its performance

#7

Post by zlatkov »

Klathmon wrote: post #4

This is somewhat off-topic, but has anyone here used SessionStack? How well does the service work, and is there a noticeable performance impact for the software to record on mid-range mobile devices? It looks really interesting and would probably be really helpful, but I can't include anything else in our applications that will further tax our already struggling lower-end devices with more code that needs to run and…

To explain just briefly, SessionStack is just collecting events from the browser like user interactions, DOM changes, etc. and then tech info like crashes, network, debug messages. All of this data is being batched in memory and sent to our servers every few seconds. And that's all the work that we do on the client-side, almost the same as any analytics tool that you already use. The "magic" happens on our end, where we're reconstructing all of this data, pulling the needed static resources, etc. in order to recreate the same series of events as they happened to your users and show you that information visually. And this happens in real-time.

Re: How JavaScript works: the rendering engine and tips to optimize its performance

#10

Post by benthehenten »

Klathmon wrote: post #4

This is somewhat off-topic, but has anyone here used SessionStack? How well does the service work, and is there a noticeable performance impact for the software to record on mid-range mobile devices? It looks really interesting and would probably be really helpful, but I can't include anything else in our applications that will further tax our already struggling lower-end devices with more code that needs to run and…

I'm not sure about the implementation in Session Stack, but I work at LogRocket (https://logrocket.com) where we're solving a similar problem. We use a few methods to ensure that we have a minimal overhead on performance.

- We use worker threads for data encoding and network I/O

- We use the MutationObserver API for capturing diffs of the DOM

- We pull static resources directly from an application's servers (vs uploading from the client)

- Loading method shims first (and later the rest of our SDK asynchronously) to reduce initial loading time

- Batching requests and waiting for network downtime to send data

- We use Protobufs as a wire format for reducing bandwidth

I'm sure Session Stack employs some similar techniques- would be curious to hear about methods they're using as well.

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