Node: ReferenceError: require is not defined

[jibrail-idris]

• Version:v12.18.0
• Platform:Linux dev 5.3.0-53-generic #47~18.04.1-Ubuntu SMP Thu May 7 13:10:50 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux
• Subsystem:require

What steps will reproduce the bug?

1. Download LTS 12.18.0 from https://nodejs.org/dist/v12.18.0/node-v12.18.0-linux-x64.tar.xz
2. Untar compressed file
3. Save a js file with the following code: (Let's called it test.js)
   console.log(require)
4. Run //node-v12.18.0-linux-x64/bin/node test.js
5. Node returns error output stating that require is not defined.

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

All the time.

What is the expected behavior?

The behavior should be similar to node executing the same one liner in REFL interactive shell.

$ node
Welcome to Node.js v12.18.0.
Type ".help" for more information.
> console.log(require)
[Function: require] {
  resolve: [Function: resolve] { paths: [Function: paths] },
  main: undefined,
  extensions: [Object: null prototype] {
    '.js': [Function],
    '.json': [Function],
    '.node': [Function]
  },
  cache: [Object: null prototype] {}
}

What do you see instead?

$ node test.js
(node:13608) ExperimentalWarning: The ESM module loader is experimental. file:///somedirectory/test.js:1 console.log(require); ^ ReferenceError: require is not defined

Additional information

The issue does not happen in older node versions. See text output below

$ node --version
v8.10.0
$ node test.js
{ [Function: require]
  resolve: { [Function: resolve] paths: [Function: paths] },
  main:
   Module {
     id: '.',
     exports: {},
     parent: null,
     filename: '/somedirectory/test.js',
     loaded: false,
     children: [],
     paths:
      [ '/somedirectory/node_modules',
      ...,
      ...,
        '/node_modules' ] },
  extensions: { '.js': [Function], '.json': [Function], '.node': [Function] },
  cache:
   { '/somedirectory/test.js':
      Module {
        id: '.',
        exports: {},
        parent: null,
        filename: '/somedirectory/test.js',
        loaded: false,
        children: [],
        paths: [Array] } } }

[richardlau]

cc @nodejs/modules-active-members

[benjamingr]

Hey thank you for the report and engaging, this is actually intentional. You cannot require from an ESM module - you need to use createRequire :]

import { createRequire } from 'module';
const require = createRequire(import.meta.url);
// can now use `require` in an ESM

See this section in the docs regarding why and how to work around it.

(I'm closing since I don't think this is a bug - as usual, if anyone feels strongly feel free to reopen)

[jkrems]

Can you verify that this happens in any directory? By default a .js file shouldn’t be treated as a module. I suspect that you may be in a directory (or nested directory below) where a package.json has a “type” field set to “module”.

[benjamingr]

BTW: Apologies, I somehow missed that OP did not realize they were running inside module context 🙏 Thanks for the comment Jan.

[BridgeAR]

Let's reopen for now.

[jibrail-idris]

@jkrems You are right. The module "type" was causing the issue. Thank you for flagging that out.

[GeoffreyBooth]

We could perhaps expand the error message to include something like “file.js is loaded as an ES module due to /path/to/package.json containing "type": "module"”

[jibrail-idris]

We could perhaps expand the error message to include something like “file.js is loaded as an ES module due to /path/to/package.json containing "type": "module"”

Yes. That will be very helpful!

[benjamingr]

Let's reopen it the meantime for the error message improvement.

[juanarbol]

I could work on this

[baselwebdev]

Thanks for this thread, was facing the same issue. More precise error message would definitely help people.

[ark334]

Hey thank you for the report and engaging, this is actually intentional. You cannot require from an ESM module - you need to use createRequire :]

import { createRequire } from 'module';
const require = createRequire(import.meta.url);
// can now use `require` in an ESM

See this section in the docs regarding why and how to work around it.

(I'm closing since I don't think this is a bug - as usual, if anyone feels strongly feel free to reopen)

Thanks so much, I was having this issue using a type:module in package.json but now it's working thanks to your solution.

[priya-concetto]

ReferenceError: createRequire is not defined

[benjamingr]

@priya-concetto did you import it from "module" ?