Make import.meta.url dynamic

[Congelli501]

Bug report

What is the current behavior?

import.meta.url is replaced by the current file location at the build time.
https://github.com/webpack/webpack/blob/main/lib/dependencies/ImportMetaPlugin.js#L99

If the current behavior is a bug, please provide the steps to reproduce.

If you build

console.log(import.meta.url)

it will ouput a constant string (le location of the file on the current system).

This is problematic to build a project using yargs (https://github.com/yargs/yargs), as it uses meta.import.url (https://github.com/yargs/yargs/blob/main/lib/platform-shims/esm.mjs#L18).

When building under an Unix file system, meta.import.url is replaced by something like file:///path/to/your/project/src/index.js. When trying to run the built code under a Windows filesystem, a TypeError [ERR_INVALID_FILE_URL_PATH]: File URL path must be absolute is thrown, as the filename doesn't contain file://C:/....

Making the meta.import.url variable dynamic (based on __dirname) should solve the problem.

What is the expected behavior?

import.meta.url should be based on __dirname for cjs build, to keep the original intended behavior of the application developer.

Other relevant information:
webpack version: 5.58.1
Node.js version: 16.10.0
Operating System: Ubuntu Linux 20.04
Additional tools: yargs

[webpack-bot]

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[alexander-akait]

Duplicate #14072

[Congelli501]

The linked issue is about supporting __dirname & __filename in a commonjs module required via an ESM module.

This issue is about supporting dynamic import.meta.url in a full ESM build, I don't think those issues are duplicates.

[alexander-akait]

But import.meta.url is file:///something/file.js, what is the problem?

[Congelli501]

It is the build time location of the file and not the run time dynamic location of the JS file

[alexander-akait]

We are doing the same for __filename in commonjs

[mika-fischer]

We are doing the same for __filename in commonjs

Yes, but that behavior can be adjusted via https://webpack.js.org/configuration/node/#node__filename and https://webpack.js.org/configuration/node/#node__dirname

We have those both set to false which means webpack will not touch __filename and __dirname at all. And we need a way to do the same for import.meta.url.

I agree that #14072 is a completely orthogonal issue and that this should be reopened.

[alexander-akait]

Make sense to allow keeping it

[Silvia813]

Any updates?

[pavelsavara]

Hi all, I tried to contribute new configuration option to fix this, but I struggle to make all tests work. I would appreciate some help.

Also I wonder what is the use-case for the current behavior, with the file name from build time. Could somebody advise ? @vankop

[dandeancook]

Also I wonder what is the use-case for the current behavior

I have a lib, which is loaded by app through http:

import libfoo from "https://bar.exampleserver.com";

and inside libfoo, it has to know whether it is loaded from in order to load other specific files for that server.

webpack-cli: 5.0.1
webpack: 5.75.0