Add a render method like Next JS

[lamualfa]

Is your feature request related to a problem? Please describe.

Small applications that use the concept of monoliths often use the API server, Frontend server and other logic in a single project. I have a little trouble to do the separation of the many routes if using the file routing concept.

Describe the solution you'd like

in Next JS, we can create a custom server using anything (like Fastify, Express, Koa, etc), then create a special handler that is used to render the React page. Next JS has its own render method which can be called from anywhere. Does Sapper have a plan to implement the same to render a Svelte page?

Example using render method in NextJS :

createServer((req, res) => {
    const parsedUrl = parse(req.url, true)
    const { pathname, query } = parsedUrl

    if (pathname === '/a') {
      // NextJS render method
      app.render(req, res, '/a', query)
    } else if (pathname === '/b') {
      // NextJS render method
      app.render(req, res, '/b', query)
    } else {
      // Other handler
      handle(req, res, parsedUrl)
    }
})

How important is this feature to you?

I am a Fastify user. I have a little trouble integrating the two. Fastify uses a quite different concept from Express to route them, so I need a render function that can be called from any route.

[antony]

It's not clear here what you're trying to achieve. Do you have a concrete example?

To create a server route in Sapper, you can just add a js file in the routes directory.

[thgh]

@antony You could see it as "page support for custom routers". Currently you can have "api routes" with .js but it's not possible to render a page component like that.

Usecases:

• pretty urls thay lead to different looking pages.
• show a login page when not authenticated for a set of pages. (solvable in _layout.svelte)
• reuse the same page component in several pages like for multilingual sites. (sort of solvable with imports)

One challenge is that the naive solution would only allow SSR because this custom routing logic is not available client-side. (could be a feature)