*command-line-args* does not survive loadFile()

[chr15m]

tl;dr: this is how you reliably get arguments across a variety of running modes:

(defn get-args [argv]
  (not-empty (js->clj (.slice argv
                              (if 
                                (.endsWith
                                  (or (aget argv 1) "")
                                  "node_modules/nbb/cli.js")
                                3 2)))))

---

version

v1.3.195

platform

Linux: Ubuntu
Node: v20.17.0

problem

You can use *command-line-args* to get args in a .cljs script, but if you then invoke that cljs script from JavaScript the args are nil.

repro

(ns args)
(print *command-line-args*)

import { loadFile } from "nbb";
await loadFile("args.cljs");

Running these:

$ npx nbb args.cljs --hello
(--hello)
$ node args.mjs --hello
nil

expected behavior

I think I would expect the output of the second command to match the first.

[chr15m]

I'm exploring ways to reliably parse out the non-script-name command line arguments.

All of this would be resolved if *command-line-args* worked consistently from inside loadFile and loadScript.

I use nbb scripts in 3 contexts:

1. Called with npx nbb scriptname.cljs
2. Called with node scriptname.mjs which then does loadFile on scriptname.cljs.
3. Called with npx nbb bundle scriptname.cljs > scriptname-bundled.mjs; node scriptname-bundled.mjs which runs the bundled version.

I would like to be able to parse the non-script-name arguments accurately in all three of these scenarios. It would actually be enough if there was just some global variable which tells me I am being run from the command line version of nbb versus being run from loadString or loadFile.

I'm not sure if these experiments will help, but I found the only reliable way to tell where to split js/process.argv is by checking if the second argument ends with node_modules/nbb/cli.js which is only true in 1. above.

Here are my test scripts:

args.cljs:

(ns args
  (:require
    [nbb.core :refer [*file* invoked-file]]))

(def in-nbb?
  (.endsWith (or (aget js/process.argv 1) "")
             "node_modules/nbb/cli.js"))

(js/console.log "*file*" *file*)
(js/console.log "invoked-file" (invoked-file))
(js/console.log "js/process.argv.1" (aget js/process "argv" 1))
(js/console.log "*command-line-args*" (clj->js *command-line-args*))
(js/console.log "process.argv" js/process.argv)
(js/console.log "Is node_modules/nbb/cli.js?" in-nbb?)
(print "Correct args list:" (.slice js/process.argv (if in-nbb? 3 2)))
(print)

args.mjs

#!/usr/bin/env node

import { addClassPath, loadFile } from 'nbb';
import { fileURLToPath } from 'url';
import { dirname, resolve } from 'path';

const __dirname = fileURLToPath(dirname(import.meta.url));

addClassPath(resolve(__dirname));
await loadFile(resolve(__dirname, 'args.cljs'));

Results of running in 3 different ways with varying arguments:

$ npx nbb args.cljs
*file* /home/chrism/dev/repro-nbb-file-bundle/args.cljs
invoked-file /home/chrism/dev/repro-nbb-file-bundle/args.cljs
js/process.argv.1 /home/chrism/dev/repro-nbb-file-bundle/node_modules/.pnpm/nbb@1.3.196/node_modules/nbb/cli.js
*command-line-args* null
process.argv [
  '/home/chrism/.nvm/versions/node/v20.17.0/bin/node',
  '/home/chrism/dev/repro-nbb-file-bundle/node_modules/.pnpm/nbb@1.3.196/node_modules/nbb/cli.js',
  'args.cljs'
]
Is node_modules/nbb/cli.js? true
Correct args list: #js []

$ npx nbb args.cljs --help
*file* /home/chrism/dev/repro-nbb-file-bundle/args.cljs
invoked-file /home/chrism/dev/repro-nbb-file-bundle/args.cljs
js/process.argv.1 /home/chrism/dev/repro-nbb-file-bundle/node_modules/.pnpm/nbb@1.3.196/node_modules/nbb/cli.js
*command-line-args* [ '--help' ]
process.argv [
  '/home/chrism/.nvm/versions/node/v20.17.0/bin/node',
  '/home/chrism/dev/repro-nbb-file-bundle/node_modules/.pnpm/nbb@1.3.196/node_modules/nbb/cli.js',
  'args.cljs',
  '--help'
]
Is node_modules/nbb/cli.js? true
Correct args list: #js [--help]

$ node args.mjs
*file* /home/chrism/dev/repro-nbb-file-bundle/args.cljs
invoked-file /home/chrism/dev/repro-nbb-file-bundle/args.cljs
js/process.argv.1 /home/chrism/dev/repro-nbb-file-bundle/args.mjs
*command-line-args* null
process.argv [
  '/home/chrism/.nvm/versions/node/v20.17.0/bin/node',
  '/home/chrism/dev/repro-nbb-file-bundle/args.mjs'
]
Is node_modules/nbb/cli.js? false
Correct args list: #js []

$ node args.mjs --help
*file* /home/chrism/dev/repro-nbb-file-bundle/args.cljs
invoked-file /home/chrism/dev/repro-nbb-file-bundle/args.cljs
js/process.argv.1 /home/chrism/dev/repro-nbb-file-bundle/args.mjs
*command-line-args* null
process.argv [
  '/home/chrism/.nvm/versions/node/v20.17.0/bin/node',
  '/home/chrism/dev/repro-nbb-file-bundle/args.mjs',
  '--help'
]
Is node_modules/nbb/cli.js? false
Correct args list: #js [--help]

$ npx nbb bundle args.cljs > args-bundled.mjs; node args-bundled.mjs
*file* null
invoked-file null
js/process.argv.1 /home/chrism/dev/repro-nbb-file-bundle/args-bundled.mjs
*command-line-args* null
process.argv [
  '/home/chrism/.nvm/versions/node/v20.17.0/bin/node',
  '/home/chrism/dev/repro-nbb-file-bundle/args-bundled.mjs'
]
Is node_modules/nbb/cli.js? false
Correct args list: #js []

$ npx nbb bundle args.cljs > args-bundled.mjs; node args-bundled.mjs --help
*file* null
invoked-file null
js/process.argv.1 /home/chrism/dev/repro-nbb-file-bundle/args-bundled.mjs
*command-line-args* null
process.argv [
  '/home/chrism/.nvm/versions/node/v20.17.0/bin/node',
  '/home/chrism/dev/repro-nbb-file-bundle/args-bundled.mjs',
  '--help'
]
Is node_modules/nbb/cli.js? false
Correct args list: #js [--help]