resolvePath output should be prefixed with kit.paths.base

[hmnd]

Describe the bug

The current output of resolvePath is not prefixed with the app's base path, making it a hassle to use with a custom base.

Reproduction

1. Set custom kit.paths.base in svelte.config.js
2. Call resolvePath()

Logs

No response

System Info

System:
    OS: Linux 6.3 Manjaro Linux
    CPU: (12) x64 Intel(R) Core(TM) i7-9750H CPU @ 2.60GHz
    Memory: 5.60 GB / 15.50 GB
    Container: Yes
    Shell: 5.9 - /usr/bin/zsh
  Binaries:
    Node: 18.16.0 - ~/.asdf/installs/nodejs/lts/bin/node
    npm: 9.5.1 - ~/.asdf/plugins/nodejs/shims/npm
    pnpm: 8.6.4 - ~/.local/share/pnpm/pnpm
  Browsers:
    Brave Browser: 114.1.52.129
  npmPackages:
    @sveltejs/adapter-auto: ^2.1.0 => 2.1.0 
    @sveltejs/adapter-cloudflare-workers: ^1.1.2 => 1.1.2 
    @sveltejs/kit: ^1.20.0 => 1.20.4 
    svelte: 4.0.0 => 4.0.0 
    vite: ^4.3.9 => 4.3.9

Severity

annoyance

Additional Information

I'm aware this would introduce a technically breaking change, so perhaps this should be exported as a separate function, or added as a flags to resolvePath to preserve current behavior.

[dummdidumm]

We can't take kit.paths.base into account automatically, because resolvePath is part of exports/index.js, which can't integrate with the generated stuff. I see two options:

• add resolvePath to $app/navigation or $app/paths, deprecate resolvePath from @sveltejs/kit and remove it in version 3
• add a third optional parameter named prefix to resolvePath, to which you can pass the base path (or anything else, if needed)

I don't know which one I like better yet, I guess it depends on how many use cases there are to use resolvePath without wanting kit.paths.base prepended.

[dummdidumm]

We're making this part of $app/paths or $app/navigation, which one we're not totally sure about yet.

[hmnd]

I would lean slightly toward putting it in $app/navigation, since

• $app/paths only provides static values
• resolvePath is (probably?) often used in tandem with goto

[benmccann]

I wasn't even aware this API existed. I might take this opportunity to rename it to resolveRoute. E.g. if you go from a domain name to an IP address, I think you call it resolving the domain name and not resolving the IP address. In this case we're going from route to path, so we should call it resolving the route.

Another option would be to put it in $app/routes. If we want to reuse an existing module then I'd probably lean more towards $app/paths since we're getting a path and we're not navigating.

[Rich-Harris]

It should definitely be $app/paths. I don't have a strong opinion on naming but resolveRoute seems fine