error message disappeared between v21 and v22

[allan-bonadio]

================================ Problem 1: missing error message
I had a file named 'ff':

#!/usr/bin/env node
import fs from 'node:fs';
console.log(`starting ff cmd`)

I ran it with node v22.9.0, and there was no response. No errror message, no starting message. Debugger breakpoints I'd set didn't break, because the program never started. (this took me like an hour to figure out.) Now I switch it over to v21.7.3 and I got the message

(node:62342) Warning: To load an ES module, set "type": "module" in the package.json or use the .mjs extension.
(Use `node --trace-warnings ...` to show where the warning was created)
/opt/GLMR5/gscripts/ff:4
import fs from 'node:fs';
^^^^^^

SyntaxError: Cannot use import statement outside a module
    at internalCompileFunction (node:internal/vm:128:18)
    at wrapSafe (node:internal/modules/cjs/loader:1279:20)
    at Module._compile (node:internal/modules/cjs/loader:1331:27)
    at Module._extensions..js (node:internal/modules/cjs/loader:1426:10)
    at Module.load (node:internal/modules/cjs/loader:1205:32)
    at Module._load (node:internal/modules/cjs/loader:1021:12)
    at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:142:12)
    at node:internal/main/run_main_module:28:49

Node.js v21.7.3

The message is also missing with v23.10.0. So, the first problem is, the error message went away, leaving no clue as to what the problem was. I'm sure you guys can fix it!

================================ Problem 2: no way to make a command line command that's esm
Then I tried to fix it with a command line option:

node --experimental-default-type=module  ff

In v23, a message says to not use --experimental-default-type=module
I also tried node --import=fs ff because somewhere it said that an --import would implicitly set it to ESM module. Didn't work.
and node --input-type=module ff didn't work.

I know I can set the suffix to .mjs and it'll work, but that's not a way to make a tidy command for end users. It makes the command look like a hack. You can make shell scripts and php executables without suffixes with the #! convension, even JavaScript if it's written in cjs, but not JS modules. This is NOT in the middle of a node package, this is just a small program that should be runable anywhere. "ff.mjs" is six characters long, whereas "ff" is two.

I can't find any other way to make a command-line command that's an ESM module. There should be such a way.Thanks for reading this far!

[ljharb]

You can't currently have an extensionless file that's ESM; see #49431. Note you can also const fs = require('node:fs'); and that script would work the same.

This should probably stay open, since it should show an error message.

[targos]

The error message that you expected is missing because there is no error. This work with all supported versions of Node.js now, including v20.19.0. That's because ES module syntax detection is enabled.

[allan-bonadio]

Well, ok, the situation without the error message seems to be that extentionless files default to CJS, and the file being ESM, has a syntax error upon the first import stmt. Then it should say something like Syntax error Cant do Import in a CJS file. Having no error message at all is usually the worst way to deal with an error situation: suddenly, the suspected causes becomes an almost infinite list.

For my limited use, I'm using a she-bang line as the first line, with the node cmd to use. If I could put in a node flag like '--module' or '--type module', I could stick this in the she-bang line and everything would work fine. Your man page for node doesn't list such a flag; nor the command-line page in the Node docs.

Also, one could make an alias like this:
alias nodem='node --type module'

[targos]

I don't understand what you're saying. There is no error. It just works. The log is printed to the console.

[allan-bonadio]

It doesn't just work. I type in the command and it quits immediately. I've tried to catch it with the debugger, and I've put print stmts in. Neither of those work. I've debugged it through some JS files but those are all nodejs internal files. Pretty much, it immediately jumps to exit. Nothing works, no error message.

example script, put it in a file named 'm' (# must be on first line of file):

#!/usr/bin/env node
import fs from 'node:fs';
console.log("emm running");

do a chmod 777 on it. Run from cmd line. does not print anything. Now, comment out the import line. Prints out, because now it's valid cjs so it prints. That's the bug.

FWIW, a flag on the node command line, I get it that not all platforms can use that with shebang. But, it would still be useful on Unix and MacOS, and it would be analogous to <script src='horse.js' type='module'>

[targos]

On macOS:

$ node -v
v23.10.0

$ cat <<EOF > ff
#!/usr/bin/env node
import fs from 'node:fs';
console.log("emm running");
console.log(fs);
EOF

$ chmod +x ff

$ ./ff
emm running
{
  appendFile: [Function: appendFile],
  appendFileSync: [Function: appendFileSync],
  ...

Same with Node.js 20.19.0, 22.9.0 and 22.14.0.