vm: constants is undefined

[ShafSpecs]

Version

22.0.0

Platform

Microsoft Windows NT 10.0.22631.0 x64

Subsystem

No response

What steps will reproduce the bug?

Import constants from node:vm. Log it, it returns undefined

How often does it reproduce? Is there a required condition?

No response

What is the expected behavior? Why is that the expected behavior?

constants is meant to return an object

What do you see instead?

undefined

Additional information

Was following along this issue: #51154
I wanted to be able to use import in my Script instance, and the constants are supposed to allow me use the default loader without flags, but the constants object is returning undefined. I am using

[Jamesernator]

It is available if you use default import:

import vm from "node:vm";

But it does seem like a bug that it isn't exposed as a named export (maybe because it's experimental?).

[targos]

Can't reproduce:

$ cat test.mjs
import { constants } from 'node:vm';
console.log(constants);

$ node test.mjs
[Object: null prototype] {
  USE_MAIN_CONTEXT_DEFAULT_LOADER: Symbol(vm_dynamic_import_main_context_default)
}

[ShafSpecs]

import { constants } from 'node:vm';
console.log(constants);

Using your same code:

$ node test.mjs
[Object: null prototype] {
  USE_MAIN_CONTEXT_DEFAULT_LOADER: Symbol(vm_dynamic_import_main_context_default)
}
# used `require` here
$ node test.cjs
[Object: null prototype] {
  USE_MAIN_CONTEXT_DEFAULT_LOADER: Symbol(vm_dynamic_import_main_context_default)
}

Both worked. I am now a tadbit confused, when I build my project and compile to bytecode, I am using the vm later on to interpret it. constants in my bytecode loader script is undefined. But it works when I just create a script in my project and node ./test.cjs directly.

This is some of the bytecode loader code:

const fs = require("fs");
const path = require("path");
const {Script,constants} = require("node:vm");
const v8 = require("v8");
const Module = require("module");
v8.setFlagsFromString("--no-lazy");
v8.setFlagsFromString("--no-flush-bytecode");
const FLAG_HASH_OFFSET = 12;
const SOURCE_HASH_OFFSET = 8;
let dummyBytecode;
console.log(constants); // logs 'undefined'
function setFlagHashHeader(bytecodeBuffer) {
  if (!dummyBytecode) {
    const script = new Script("", {
      produceCachedData: true,
      // trying to actually use it here
    });
    dummyBytecode = script.createCachedData();
  }
  dummyBytecode.slice(FLAG_HASH_OFFSET, FLAG_HASH_OFFSET + 4).copy(bytecodeBuffer, FLAG_HASH_OFFSET);
};
// ....

[joyeecheung]

Maybe somehow you are not using the right version of Node.js that has vm.constants to load it?

[ShafSpecs]

Maybe somehow you are not using the right version of Node.js that has vm.constants to load it?

Running process.versions.node pretty much answered it. I am using version 20 at runtime, but my version is 22. Not sure how to force an upgrade, I tried nvmrc, npmrc, engine strict, and engines config but they didn't do it. Might be a case of my project dependencies bundled with node 20?

[RedYetiDev]

Hi, it seems the issue was resolved, but if anyone disagrees, please re open this issue