Import map expansion doesn't work in LSP

[dsherret]

{
  "imports": {
    "preact": "npm:preact@10.5.13"
  }
}

import * as preact from "preact";
import * as hooks from "preact/hooks"; // error only in lsp

console.log(preact, hooks);

Version: Deno 1.40.3

[lucacasonato]

It also doesn't work in deno publish I think unrelated issue

[guybedford]

If the import map is defined only for preact, expansion / inference of preact/hooks seems to violate the import maps spec? Or is the idea to bend the semantics to better support packaging workflows in this way?

[dsherret]

Sorry, wasn't clear in the issue. This is only for the embedded import map in deno.json (not if referenced via "importMap": "..."), which is an extension to the import map spec. It only occurs for jsr and npm imports because it was an annoyance to have two entries (#22087)

[guybedford]

Thanks for sharing the context, I missed that. I guess this only makes sense because the targets are not so much final URLs as they are intermediate package specifiers which then get further resolution processing applied. If browsers were ever to adopt the same pattern they would effectively rely on /dir serving the main entry point and /dir/module serving submodules, while while very unlikely to ever be viable, doesn't seem entirely unreasonable either, so it seems an interesting extension to explore. I would be careful of extending the spec much further at all though, effectively these are already two extensions which simply won't be supported by Node.js (partial resolution into intermediate specifier targets and automatic subpathing expansion).

[dsherret]

@nayeemrmn I'll take this one on by making this happen at a lower level.