[andrewfong]

By virtual DOM, what I mean is telling the browser I would like to replace the innerHTML of an element with another bit of HTML, and the browser should figure out an efficient way to "diff" the update rather than replace all the children wholesale.

It would not be as efficient as Svelte and Solid since those can use the compiler to further optimize code, but having the framework-less version of JS be "as good as" a framework like Vue or React would be a big plus for moving away from frameworks generally.

Apart from that, the general problem of reactivity boils down to "map this DOM element to this variable, and if the variable changes, update the DOM element". You could imagine an API sort of like this:

  <span bind-var="variableName" bind-gen="functionName">
    Default Value
  </span>

Where `bind-var` specifies a variable that, if updated, signals that the span should be replaced with the return value of the function specified by `bind-gen`

[josephg]

> By virtual DOM, what I mean is telling the browser I would like to replace the innerHTML of an element with another bit of HTML, and the browser should figure out an efficient way to "diff" the update rather than replace all the children wholesale.

Yeah, I know what you mean. And I agree that something like that could be faster than react if it were written in C++. But if we're going to bake something into the browser, I'd like it to be something good. The "Regenerate big chunks of HTML then do expensive tree-diffing operations" approach is, as you say, always going to be less efficient than how Svelte or Solid render. I'd much rather skip DOM diffing entirely and go straight to that.

> Where `bind-var` specifies a variable that, if updated, signals that the span should be replaced with the return value of the function specified by `bind-gen`

Nice - thanks for the example. I suppose the trick is implementing this in such a way that it doesn't depend on "watching" a variable in javascript. (Well, or we'd need to also add that as a feature to javascript - which would be a bit wild.)