webpack/lib/node/NodeOutputFileSystem removed in Wepback 5

[JoshuaKGoldberg]

• Operating System: Mac 10.14.5
• Node Version: 8.9 (but it's not relevant to this issue)
• NPM Version: Yarn 1.15.2
• webpack Version: 5.0.0-alpha.17
• webpack-dev-middleware Version: 3.7.0

Expected Behavior

Don't crash when starting a Webpack dev server.

Actual Behavior

Error: Cannot find module 'webpack/lib/node/NodeOutputFileSystem'
Require stack:
- ../node_modules/webpack-dev-middleware/lib/fs.js
- ../node_modules/webpack-dev-middleware/index.js
- ../node_modules/webpack-dev-server/lib/Server.js

Code

const NodeOutputFileSystem = require('webpack/lib/node/NodeOutputFileSystem');

const { mkdirp } = new NodeOutputFileSystem();

mkdirp in NodeOutputFileSystem is directly require("mkdirp") per #405. I think this issue would be fixed if fs.js directly had const mkdirp = require("mkdirp"); instead.

How Do We Reproduce?

Try out the Webpack 5 alpha: webpack/webpack#8537

Issue reported on that thread: webpack/webpack#8537 (comment)

[alexander-akait]

Yes, you are right, PR welcome