denoland/deno · error

Unknown package kind: {}

Error message

Unknown package kind: {}

What it means

`deno init` only scaffolds from a template package when the package value starts with `jsr:` or `npm:` (routed to init_jsr/init_npm). This bail is a defensive guard for a package value that carries neither prefix. The argument parser normally rejects unprefixed names earlier with a 'Missing jsr: or npm: prefix' message, so seeing this specific text usually means an internal routing edge rather than ordinary CLI usage.

Source

Thrown at cli/tools/init/mod.rs:46

use crate::colors;
use crate::util::env::resolve_cwd;
use crate::util::temp::create_temp_node_modules_dir;

pub async fn init_project(
  flags: Flags,
  init_flags: InitFlags,
) -> Result<i32, AnyError> {
  if let Some(package) = &init_flags.package {
    if package.starts_with("jsr:") {
      return init_jsr(package, init_flags.package_args, init_flags.yes)
        .boxed_local()
        .await;
    } else if package.starts_with("npm:") {
      return init_npm(package, init_flags.package_args, init_flags.yes)
        .boxed_local()
        .await;
    } else {
      bail!("Unknown package kind: {}", package);
    }
  }

  let cwd = resolve_cwd(flags.initial_cwd.as_deref())?;
  let dir = if let Some(dir) = &init_flags.dir {
    let dir = cwd.join(dir);
    std::fs::create_dir_all(&dir)?;
    Cow::Owned(dir)
  } else {
    cwd
  };

  if init_flags.empty {
    create_file(
      &dir,
      "main.ts",
      r#"console.log('Hello world!');
"#,

View on GitHub (pinned to 9ad36f7a2c)

Solutions

1. Use an explicit prefix: `deno init npm:vite` or `deno init jsr:@fresh/init`
2. Or use the flags: `deno init --npm vite` / `deno init --jsr @fresh/init`
3. For a plain local starter project, use `deno init [dir]` with no package argument

Example fix

# before
deno init vite

# after
deno init npm:vite
# or
deno init --npm vite
# plain local project instead:
deno init my_project

# validate the package spec before calling init in scripts:
case "$pkg" in jsr:*|npm:*) deno init "$pkg" ;; *) echo "prefix with jsr: or npm:" >&2; exit 1 ;; esac

// JS wrapper
class PkgSpec {
  static isTemplateSpec(s) {
    return s.startsWith("jsr:") || s.startsWith("npm:");
  }
}

Catch init failures; if the message mentions package kind/prefix, re-run with the corrected `npm:`/`jsr:`-prefixed specifier or fall back to plain `deno init <dir>`.

When it happens

Trigger: init_flags.package is Some(...) but the string lacks both prefixes — possible via internal API misuse, a future flag path that sets package directly, or a custom build of the CLI; user-level equivalents like `deno init --npm ''`-style oddities are caught at parse time instead.

Common situations: Users typing `deno init vite` expecting a template and getting the parser's prefix error (the sibling of this guard); forks/embedders constructing InitFlags by hand.

Related errors

• Invalid type for fetch: must be a function
• Invalid type for onListen: must be a function
• ERR_PARSE_ARGS_INVALID_OPTION_VALUE
• ERR_PARSE_ARGS_UNKNOWN_OPTION
• ERR_INVALID_ARG_VALUE

AI-assisted analysis of denoland/deno@9ad36f7a2c (2026-08-20). Data as JSON: /api/errors/2fe2e5daec0e2fce. Report an issue: GitHub.