The WEBPACK_DEV_SERVER environment variable is not set when running "webpack serve"

• Operating System: macOS Catalina 10.15.7
• Node Version: 12.18.3
• NPM Version: 6.14.6
• webpack Version: 5.1.3
• webpack-dev-server Version: “3.10.3”
• Browser: any

• This is a bug
• This is a modification request

Code

console.log(process.env.WEBPACK_DEV_SERVER);

Put the above in a webpack.config.js executed via:

webpack serve

Expected Behavior

I would expect the console.log to print true or 1. I am not sure what used to be the value for this environment variable but I am sure it used to be there.

Actual Behavior

undefined is printed.

How can we reproduce the behavior?

Simply place the above console.log inside any webpack.config.js that is run via webpack serve.

[bensampaio]

Well it used to work when running webpack-dev-server directly so why doesn’t it work with webpack serve? After upgrading to webpack 5 I had to change to webpack serve because webpack-dev-server didn’t work anymore due to this issue: https://github.com/webpack/webpack-dev-server/issues/2029#issuecomment-707034614.

If this was expected behavior with the transition to webpack 5 then I would at least expect this to be documented in the migration guide instead of closing this issue as if was meant to be obvious that this is not possible…

[alexander-akait]

WEBPACK_DEV_SERVER only for custom running, no WEBPACK_DEV_SERVER in webpack.config.js, because we can’t know about it, you can use multi compiler mode, you can use env variables for this