Doesn't work with `npm:` specifiers about esbuild_deno_loader

[bartlomieju]

@codesculpture, @itsdouges and I are looking into this problem

[Ciantic]

I made a plugin to rewrite npm:... to esm.sh before deno plugin like this:

await esbuild.build({
    plugins: [
        // ESBuild plugin to rewrite import starting "npm:" to "esm.sh" for https plugin
        {
            name: "the-npm-plugin",
            setup(build: any) {
                build.onResolve({ filter: /^npm:/ }, (args: any) => {
                    return {
                        path: args.path.replace(/^npm:/, "//esm.sh/"),
                        namespace: "https",
                    };
                });
            },
        },
        denoPlugin() as any,
    ],

However it doesn't utilize the cache, it seems to be downloading all of the files I rewrite like that on each build.

Also it seems to be that tree shaking doesn't work for those imports (currently I use it to just date-fns) which is a bummer.

But it works for the time being.

---

Edit I also noticed I can get it to work like this:

import_map.json

{
    "imports": {
        "npm:date-fns": "https://esm.sh/date-fns"
    }
}

denoPlugin({
    importMapURL: new URL("./import_map.json", import.meta.url),
}) as any,

Problem with this approach is the same as with my plugin above, the esbuild command re-downloads the URLs each time. In my example it re-downloads https://esm.sh/date-fns on each build and it makes it slow.

[mitchwadair]

Is there any work being done on this at the moment?