The import_map.json file generated by deno vendor doesn't contain the imports of the existing import_map.json. This makes script to fail because these import entries are missing.

As an example, Lume uses the following import map:

{
  "imports": {
    "lume/": "https://deno.land/x/[email protected]/"
  }
}

To vendor a Lume project, the script take 2 lume files and the _config.ts file:

deno vendor \
https://deno.land/x/[email protected]/task.ts \
https://deno.land/x/[email protected]/cli.ts \
./_config.ts

The vendor/import_map.json file doesn't include the lume/ import, so it fails.

Lume has a lume vendor command to run deno vendor and fix the new import_map.json file by adding automatically the missing imports (https://github.com/lumeland/lume/blob/f9866692391ed4d7500494b9d2b29de0921f9f26/cli/vendor.ts#L55-L63) but I think this is something that Deno should do.