I’ve been wondering about this for a while and haven’t really found a great answer for it. From what I understand, WASM is:

  • Faster than JavaScript

  • Has a smaller file size

  • Can be compiled to from pretty much any programming language

  • Can be used outside of the browser easier thanks to WASI

So why aren’t most websites starting to try replacing (most) JS with WASM now that it’s supported by every major browser? The most compelling argument I heard is that WASM can’t manipulate the DOM and a lot of people don’t want to deal with gluing JS code to it, but aside from that, is there something I’m missing?

  • pileghoff
    131·
    1 year ago

    I think the truth is that not only can’t WASM manipulate the DOM, but javascript was build to manipulate the DOM and has been moulded around this purpose. Secondly, if you want to use WASM from another programming language, that is just another language you need to learn on top of javascript, because we are not at a stage where we can replace javascript (because of the DOM). Fo most it’s more cost effective to just optimize their javascript code instead of adding another layer to the tech stack.

    • nousEnglish
      3·
      1 year ago

      I think the truth is that not only can’t WASM manipulate the DOM

      Not directly no. But it can via JS (without the developer needing to ever touch JS code themselves via auto generated bindings). And this is simply a limitation of the current WASM implementations/standards. I believe there is work on going to get WASM more direct access to the DOM. But really this will just be an efficiency improvement over what is currently possible (which is already possibly to be as fast as pure JS frameworks).

      Secondly, if you want to use WASM from another programming language, that is just another language you need to learn on top of javascript, because we are not at a stage where we can replace javascript (because of the DOM).

      This is not quite true. Yes we cannot replace JS currently. But you don’t need to learn JS to develop using WASM - there is already enough tooling that can auto generate any JS code needed for you so developers never actually need to learn or touch JS if they don’t want to.

      But existing developers that already know JS don’t have a huge reason to learn another language that only have a vastly less mature ecosystem. So the door is currently open for those that don’t enjoy or want to touch JS, but those people will at this point in time be working on other things rather then web apps. So there is not going to be a huge push for moving to a different language with WASM support any time soon. Not to mention that there is only minor benefits to existing applications that make a full rewrite to another language not worth the effort. So people wont be flocking over toward it, but not for the reasons you mentioned.

      • pileghoff
        3·
        1 year ago

        Sure, you can autogenerated js bindings, but as soon as you need to start debugging or optimizing you need to understand the js that was generated for you.

        • nousEnglish
          2·
          1 year ago

          I don’t think so. Having played around with wasm-bindgen in rust as well as other libraries the build on top of it I have never once needed to look at or understand the generated JS code. When you need to debug or optimise things the first thing to look at is the rust code. So as it stands today I do not think you need to know JS to write code for a web frontend - at least in isolation of anything else (ie teams, existing products etc).

          You will likely need to learn JS at some point when writing stuff for the web - as the JS ecosystem is so vast for web development when compared to anything else. But WASMs JS bindings are not the point you will need to know it for.