[Feature] Add ?path= query parameter to improve Deno/importMap compatibility

[pauljoey]

Hi! Love the project!

I'm really hoping to turf NPM and build system complexity often required for consuming third-party libraries (especially in the front-end). esm.sh really helps with that.

My use case: I'm really interested in the idea of using Deno + esm.sh as a build system for front-end projects.

I'm using an importMap to resolve named dependencies - a feature which I think has a non-zero chance of becoming a future ecmascript standard. It isn't strictly necessary but many existing files use this style so it's useful to try and support it.

import Button from '@mui/material/Button';

With imports.json

{
  "imports": {
    "@mui/material/": "https://esm.sh/@mui/material@5.3.0/",
  }
}

This works fine with Deno. The only problem is that esm.sh detects the Deno UA and (appropriately) I end up building a version for the Deno runtime - not the browser. No problem, I just need to specify ?target=esnext. The only problem now is that in so doing (or adding any query string parameters), imported paths are no longer constructed correctly. @mui/material/Button becomes https://esm.sh/@mui/material@5.3.0/?target=esnextButton

My suggestion would be to simply add support for a ?path query string parameter (or ?subpath?) which would be appended (if specified) to the url path to determine the path of the requested resource.

So

https://esm.sh/@mui/material@5.3.0?target=esnext&path=/Button

would be equivalent to

https://esm.sh/@mui/material@5.3.0/Button?target=esnext

[ije]

@pauljoey this looks great, i will add this feature asap

[ije]

added in v65