This line in entry array does not play well with webpack-dev-server:
webpack-hot-middleware/client
because it’s a requirement of webpack-hot-middleware for working with any server other than webpack-dev-server (such as express or some such).
I ran into this mixed-server issue by following Webpack tutorials. They should update it so that the entry point for the config file of Webpack using webpack-dev-server doesn’t require an artifact produced by webpack-hot-middleware, which tries to hot-emit the developer’s module updates into a custom-built server depending on it.
You can remove that line from the entry array, which in case of using dev-server should solve the problem.
FYI That line in your code came from here:
https://github.com/webpack-contrib/webpack-hot-middleware
where it says:
Add
webpack-hot-middleware/client?...into the
[webpack config’s] entry array. This connects to the server to receive
notifications when the bundle rebuilds and then updates your client
bundle accordingly.
Based on your question, “I’m using webpack-dev-server”, you’re therefore not using “webpack-hot-middleware” and should remove the entry line.