Webpack-cli: support `webpack.config.cjs` by default

[xiaoxiangmoe]

If a webpack.config.js is present, the webpack command picks it up by default. We use the --config option here only to show that you can pass a config of any name. This will be useful for more complex configurations that need to be split into multiple files.

We should also pick it up when a webpack.config.cjs is present

[ematipico]

This requires a minimum version of node right?

[xiaoxiangmoe]

No, we can just regard cjs as js

[smelukov]

Seems like we can't just support it - https://github.com/gulpjs/interpret/issues/65

[ExE-Boss]

Actually, you can, as .cjs can be used anywhere a .js file can be used currently, which both the docs and the source code confirm.

[Parikshit-Hooda]

Hi. Can I take up this issue? @ematipico

[Parikshit-Hooda]

Hi. I have made some changes, how do I test that the changes resolve the issue?
Specifically, I have made changes to the 'packages/webpack-cli/lib/groups/configGroup.js' file to include support for '.cjs' file. Thanks.

[snitin315]

how do I test that the changes resolve the issue

@Parikshit-Hooda As this is a new feature you are implementing you have to write your own tests.

Also, you can run the current tests with yarn test

[Parikshit-Hooda]

@snitin315 Actually, I want to confirm if the feature addition actually fixes this issue or not? I imagine that the modified repo(fixed webpack-cli) will need to be imported in a dummy project and check. How do I go about checking this?

[snitin315]

you can use npm link or yarn link

[Parikshit-Hooda]

Haven't done this kind of an activity before. Can you please elaborate or tell me what exactly should I google?

[anshumanv]

Haven't done this kind of an activity before. Can you please elaborate or tell me what exactly should I google?

You need to run your changes locally, https://docs.npmjs.com/cli/link.html
Link the package and try to run with a .cjs config file then write tests for it.

[Parikshit-Hooda]

Question: Should I link the repo after following the contributing.md and making edits or without following the instructions in CONTRIBUTING.md. I am asking because I am not sure if going through yarn install ->bootstrap -> build causes some unrequired changes.

[anshumanv]

build causes some unrequired changes.

What are the unrequired changes?

Yep please install, bootstrap, build then link the webpack-cli package in the packages folder.

Then you need to npm link webpack-cli in a folder, that folder will then use the local code that you have.

Question: Should I link the repo after following the contributing.md and making edits or without following the instructions in CONTRIBUTING.md.

Yes, after following the steps.

[Parikshit-Hooda]

After linking it, its still requiring me to 'npm install webpack-cli' to run the npm run build. What am I doing wrong?

[anshumanv]

Invoke using webpack-cli, after you run npm link webpack-cli in your test folder.

[Parikshit-Hooda]

Doesn't seem to work.
$ webpack-cli --entry src/index.js --config webpack.config.cjs
bash: webpack-cli: command not found

[anshumanv]

You didn't symlink properly then.

[Parikshit-Hooda]

got it. will raise a PR in a couple of days.

[Parikshit-Hooda]

Alternative solution: wondering if replacing the extension '.cjs' with '.js' is a better solution?
Reason: I was going through the file that is to be edited and 'webpack.config.js' is actually used as a primitive default variable and the variable scope is dispersed and large. changing the extension is hence a simpler solution. Also, if anybody has a suggestion which files actually need to be inspected for this feature, do let me know!

[ExE-Boss]

.js is parsed as an ECMAScript module when package.json has type: "module" specified.

.cjs is always parsed as a CommonJS module, which is the only module format which webpack currently supports for its configuration files.

[anshumanv]

^
+

Alternative solution: wondering if replacing the extension '.cjs' with '.js' is a better solution?

Nope, as stated above they are interpreted differently, so not a good solution.

[tcodes0]

.js is parsed as an ECMAScript module when package.json has type: "module" specified.

.cjs is always parsed as a CommonJS module, which is the only module format which webpack currently supports for its configuration files.

Hey yall. Is it currently planned to support esm for config files? I guess it would raise the minimum node version way too high right?