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I'm having a hard time squaring this statement: > I've been a mobile developer for 10 years, a web developer for 2-3 years, and I've done perf with C++/Asm for

I'm having a hard time squaring this statement: > I've been a mobile developer for 10 years, a web developer for 2-3 years, and I've done perf with C++/Asm for years of my career, so know that I'm not coming from a place of naivete on either performance or mobile/web development. with this: > Is the DOM – from which is derived from HTML – not also a component tree? Is it a graph or some other topology I'm not aware of? When you specify a design in Interface Builder, Android xml, or even the DOM-differ-like SwiftUI + Jetpack Compose how is the topology different? Check a DOM object, it's a node with children.

h0l0cube 4y ago
> I'm having a hard time squaring this statement Would you like to point out where I'm mistaken? Or are you just feigning superiority? DOM objects can have exactly one parent, many children, and cannot have cycles (i.e, no parent can be itself or a child). It's very specifically a tree[0] of components. I'll take the L here if I can learn something from you. So tell me, with accuracy, how HTML/DOM is not a component tree? And then extra points as to why this different data structure is inherently less performant. [0] https://en.wikipedia.org/wiki/Tree_(data_structure) https://en.wikipedia.org/wiki/Tree_(data_structure)
- etchalon 4y ago
  In a discussion about the performance tradeoffs inherent in abstractions, you seem to be implying you don't understand why a tree of say, NSViews, would be more performant than the process of parsing text markup, converting that markup into a tree which in turn may/would have a component tree attached, which may include a mixture of platform-provided components and internal components, maintaining state between the DOM's tree, the component tree and potentially platform components in a highly-dynamic environment which has to expose and allow for mutations on it's internal state to an interpreted runtime. I'd recommend reading through WebCore, from the WebKit project, as its some of the most readable CPP you'll find, and should give a sense of why that implication is naive: https://github.com/WebKit/WebKit/tree/main/Source/WebCore https://github.com/WebKit/WebKit/tree/main/Source/WebCore
  - h0l0cube 4y ago
    Of course the best thing to do when you have an unwinnable argument is to change the argument, but I'll move with you. > converting that markup into a tree The web is indeed dynamic. It means any cache-misses for webpages will require re-parsing. Could be substantial compute depending on the size of the page, but not necessarily – the vast majority of the delay of a webpage is network. But we're talking a web app here. If it is something visited often (as one would use an app), it's a cache-hit, if it's occasional usage, it's analogous to downloading an app again, but much faster and without having to jump to the app store to do it. > which in turn may/would have a component tree attached Read my earlier comment. Component trees are not a point of difference here. > maintaining state between the DOM's tree Once again, not a point of difference. DOM manipulation is component tree manipulation, much the same as what's happening under the hood in SwiftUI and Jetpack Compose. > to an interpreted runtime Once again, if you're not using an app often, there's a cache-miss and the code will need to be re-parsed, but that's the trivial 'download cost' of the app. Once parsed it's JITable byte code much like Dalvik on Android. > I'd recommend reading through WebCore That's cute. Given this whole thread I'd wager you've never read it before, let alone grokked it any of it. You're probably capable of doing so, and you're welcome to, but I'll make no pretense of having read it or intending to. Caching and execution of dynamic JS was a difficult problem, but one that has received a lot of attention. Similarly caching of dynamic HTML and CSS. These performance problems are fortunately the purview of specialized developers building one of the 3 browser engines in popular use and complexity well abstracted from the developer. There is one main drawback, which you haven't mentioned yet, that is memory and storage. But once again, because it's cached, it's very easy to 'eject' a web app from storage (e.g. using an LRU policy). But of course the elephant in the room is that many popular 'native' apps are just Ionic/Electron ports[0], because people gave up waiting for PWAs to be supported fully by mobile OS and browser engine teams. I've used 1Password, Spotify, Slack, Signal, etc. built on HTML/CSS/JS and I don't experience jank, because the performance problems have been solved. You might retort, "But they aren't dynamically loaded", to which I'd point you to back to the concept of caching. [0] https://en.wikipedia.org/wiki/List_of_software_using_Electron https://en.wikipedia.org/wiki/List_of_software_using_Electro... And with that, I'm done here.
    - 4y ago

h0l0cube 4y ago

> I'm having a hard time squaring this statement Would you like to point out where I'm mistaken? Or are you just feigning superiority? DOM objects can have exactly one parent, many children, and cannot have cycles (i.e, no parent can be itself or a child). It's very specifically a tree[0] of components. I'll take the L here if I can learn something from you. So tell me, with accuracy, how HTML/DOM is not a component tree? And then extra points as to why this different data structure is inherently less performant. [0] https://en.wikipedia.org/wiki/Tree_(data_structure) https://en.wikipedia.org/wiki/Tree_(data_structure)

etchalon 4y ago
In a discussion about the performance tradeoffs inherent in abstractions, you seem to be implying you don't understand why a tree of say, NSViews, would be more performant than the process of parsing text markup, converting that markup into a tree which in turn may/would have a component tree attached, which may include a mixture of platform-provided components and internal components, maintaining state between the DOM's tree, the component tree and potentially platform components in a highly-dynamic environment which has to expose and allow for mutations on it's internal state to an interpreted runtime. I'd recommend reading through WebCore, from the WebKit project, as its some of the most readable CPP you'll find, and should give a sense of why that implication is naive: https://github.com/WebKit/WebKit/tree/main/Source/WebCore https://github.com/WebKit/WebKit/tree/main/Source/WebCore
- h0l0cube 4y ago
  Of course the best thing to do when you have an unwinnable argument is to change the argument, but I'll move with you. > converting that markup into a tree The web is indeed dynamic. It means any cache-misses for webpages will require re-parsing. Could be substantial compute depending on the size of the page, but not necessarily – the vast majority of the delay of a webpage is network. But we're talking a web app here. If it is something visited often (as one would use an app), it's a cache-hit, if it's occasional usage, it's analogous to downloading an app again, but much faster and without having to jump to the app store to do it. > which in turn may/would have a component tree attached Read my earlier comment. Component trees are not a point of difference here. > maintaining state between the DOM's tree Once again, not a point of difference. DOM manipulation is component tree manipulation, much the same as what's happening under the hood in SwiftUI and Jetpack Compose. > to an interpreted runtime Once again, if you're not using an app often, there's a cache-miss and the code will need to be re-parsed, but that's the trivial 'download cost' of the app. Once parsed it's JITable byte code much like Dalvik on Android. > I'd recommend reading through WebCore That's cute. Given this whole thread I'd wager you've never read it before, let alone grokked it any of it. You're probably capable of doing so, and you're welcome to, but I'll make no pretense of having read it or intending to. Caching and execution of dynamic JS was a difficult problem, but one that has received a lot of attention. Similarly caching of dynamic HTML and CSS. These performance problems are fortunately the purview of specialized developers building one of the 3 browser engines in popular use and complexity well abstracted from the developer. There is one main drawback, which you haven't mentioned yet, that is memory and storage. But once again, because it's cached, it's very easy to 'eject' a web app from storage (e.g. using an LRU policy). But of course the elephant in the room is that many popular 'native' apps are just Ionic/Electron ports[0], because people gave up waiting for PWAs to be supported fully by mobile OS and browser engine teams. I've used 1Password, Spotify, Slack, Signal, etc. built on HTML/CSS/JS and I don't experience jank, because the performance problems have been solved. You might retort, "But they aren't dynamically loaded", to which I'd point you to back to the concept of caching. [0] https://en.wikipedia.org/wiki/List_of_software_using_Electron https://en.wikipedia.org/wiki/List_of_software_using_Electro... And with that, I'm done here.
  - 4y ago