Webpack v4 and v4-beta support

[lencioni]

• This is a bug
• This is a modification request

Now that webpack v4-beta.0 has been released, there are no more expected breaking changes before the v4 full release in a few weeks. It would be great to publish a version of webpack-dev-server that aims to add support for this new version so folks can start to test their stuff.

I found #1243 which could be a good start for this, but I figured I'd open an issue for folks to track if they are interested in this in general.

[dschissler]

I've been caught twice now trying to upgrade Webpack during late beta and getting through the config changes only to realize that it was a waste of time since webpack-dev-server wasn't yet supported. This happened to me on v1 -> v2 and now v3 -> v4.

I have a question if the serious developers are not using dev-server in their big projects because I can't see how it would be ideal to do a final beta when the two haven't yet been tested together to see if there are unforeseen limitations. The dev-server isn't as first class as I'd like. I guess that for now I'll just set this code aside, rollback, remove npm links. Its annoying.

[drwpow]

I’m having an issue with code-splitting in v4-beta + WDS (in addition to the fun yargs issue mentioned).

Code-splitting is trying to load chunks relatively from the path it’s on, rather than absolutely from the root. E.g., if you’re on /pages/about, the chunk is 404-ing trying to load from /pages/1.js rather than /1.js like v3 did.

Not sure if this is a WDS issue or a webpack v4 issue.

Example here: https://github.com/dangodev/webpack-v4-code-splitting-test

[damonbauer]

@DangoDev This was just posted a few hours ago, it might be related: https://medium.com/webpack/webpack-4-import-and-commonjs-d619d626b655

[drwpow]

@damonbauer nice! Just read through that. That’s helpful info, but I don’t think that’s affecting this issue.

I opened an issue on the core repo. I’m thinking now it’s a webpack thing, not a webpack-dev-server thing.

[SpaceK33z]

Please test the latest beta, webpack-dev-server@3.0.0-beta.1. Also be sure to read the changelog.

[drwpow]

@SpaceK33z when passing arguments via CLI (e.g., "start": "webpack-dev-server --hot"), it seems to require installing webpack-cli for yargs. Is this intentional, or a bug?

[SpaceK33z]

It intentionally requires webpack-cli, yes.

[esamattis]

Found couple of issues with the new defaults in Webpack 4.

Versions:

• webpack-dev-server 3.0.0-beta.1
• webpack 4.0.0-beta.1

Config:

var config = {
    mode: "development",
    module: {
        rules: [
            {
                test: /\.jsx?$/,
                exclude: /node_modules/,
                loader: "babel-loader",
            },
        ],
    },
};

As the entry is not defined following error is thrown:

Invalid configuration object. Webpack has been initialised using a configuration object that does not match the API schema.
 - configuration.entry should be one of these:
   object { <key>: non-empty string | [non-empty string] } | non-empty string | [non-empty string] | function
   -> The entry point(s) of the compilation.
   Details:
    * configuration.entry should be an object.
      -> Multiple entry bundles are created. The key is the chunk name. The value can be a string or an array.
    * configuration.entry should be a string.
      -> An entry point without name. The string is resolved to a module which is loaded upon startup.
    * configuration.entry[1] should be a string.
      -> A non-empty string
    * configuration.entry should be an instance of function
      -> A Function returning an entry object, an entry string, an entry array or a promise to these things.

It works if I define it to entry: "./src/index.js" but that should not be required with Webpack 4 as it's the default.

Another related thing is that the bundle should be served from /dist/main.js. It seems that it's not served at all. This can be fixed by setting:

output: {
    publicPath: "/dist",
},

But it's useable otherwise. Thank you!

[SpaceK33z]

@epeli do you also get this error when you are using webpack instead of webpack-dev-server?

[esamattis]

Nope, the weppack command works as expected.

[SpaceK33z]

@epeli see #1308 for that error.

I'm going to close this since the latest beta works with webpack v4 now. Let's create separate issues for new problems.