The behavior of the "parse" function when used without arguments is strange.

[KaminoRyo]

Issue Type

• Bug Report
• Feature Request
• Other

Hi. I am attempting to create my first Node.js CLI program.

const cli = cac("sample-app");
cli.command("hello", "say hello world").action(() => {
  console.log("Hello World!");
});
const parsed = cli.parse();
console.log(parsed);

I ran this sample code using the npx vite-node index.ts hello command.

Expected

"Hello World!" is being printed.

Actual

"Hello World!" is not being printed.There are no errors.The help() and version() commands are working as expected.

Possible Solutions

Upon investigation, I found that using parse(process.argv) results in "Hello World!" being printed when no arguments are provided, while the parsed object logged in both cases shows the differences:

No arguments provided (incorrect)

{ args: [ 'index.ts', 'hello' ], options: { '--': [] } }

Using process.argv as arguments (correct)

{ args: [], options: { '--': [] } }

It appears that the code processes arguments differently when no arguments are provided, and it seems to be related to Deno's Deno.args.
I'm not familiar with Deno, so this difference is a puzzling.

Info

• CAC version: 6.7.14
• Reproduction link:

[Bryandero98]

Hi! I'd like to work on this — I maintain a CLI tool (cliguard) with a CAC adapter, so I'm quite familiar with cac's parsing internals. Could you assign this issue to me before I open a PR? Thanks!

[Bryandero98]

Follow-up: I was not able to reproduce this on current main. Verified twice with the exact repro from this issue (npx vite-node index.ts hello), once in a fresh directory and once against a clean checkout — parse() resolves the correct CLI args in both cases.

My best guess is this was fixed as a side effect of b943ceb ("feat: support on browsers"), which rewrote the old src/node.ts argv-detection logic into the current src/runtime.ts, after this issue was filed.

Rather than claim a fix for something that no longer reproduces, I opened #174 adding regression coverage instead: the existing test suite only ever exercised parse()'s no-argv fallback via plain node subprocesses, with no coverage for an alternative runtime like vite-node (which is exactly what this issue was about). Happy to close this issue if you agree it's resolved, or to dig further if you can still reproduce it on your end — let me know what you're seeing if so.

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