Disable SSR (and CSR!)

[Rich-Harris]

People often ask for SPA mode. We could do the following:

// svelte.config.js
module.exports = {
  adapter: '@sveltejs/adapter-node',
  serverSideRendering: false
};

(serverSideRendering: false might seem nonsensical in the context of adapter-node — why not just use adapter-static? — but we might still have dynamic endpoints, so it's something that should probably work with all adapters.)

Less commonly, people ask to disable client-side rendering (i.e. they just want SSR'd HTML, no interactivity) or at least client-side routing.

So we could have three new options that all default to true:

• serverSideRendering
• clientSideRendering
• clientSideRouting

At least one of serverSideRendering or clientSideRendering would have to be true, and clientSideRouting couldn't be false if serverSideRendering was false.

[dummdidumm]

Would an enum make this more clear so people cannot end up in impossible config states?

[benmccann]

What is clientSideRendering without clientSideRouting or vice versa? I'm half feeling like the answer should be obvious to me, but at the same time I'm having a really hard time separating those in my mind

[Rich-Harris]

clientSideRendering: false means 'don't run JS at all'. clientSideRouting: false means 'run JS, i.e. render/hydrate the component that defines the page we land on, but don't load/start the router, navigation will result in a full page reload'.

Obviously you couldn't have clientSideRendering: false, clientSideRouting: true, because you can't have client-side routing without loading JS.

What would the enum look like? It's easy enough to prevent impossible config states — we just throw an error

[isgj]

Is it reasonable that the first steps for this feature will be

1. make https://github.com/sveltejs/kit/blob/master/packages/kit/src/runtime/client/router.js able to start on the browser depending on the path
2. add to https://github.com/sveltejs/kit/blob/master/packages/kit/src/core/adapt/Builder.js a method that will output (copy) a .html file without rendering the part of the target of app.html, and that in the script part will use the router as in point 1

?