dev server does not start

[whohoho]

#npm --version
5.6.0
#npm install webpack-dev-server
#npm install webpack

#node dev-server.js
NODE_ENV [undefined] Prod: false Devel: true
Development, using as environment variables: {"DEVELOPMENT":"true","NODE_ENV":""development"","API_ROOT":""http://localhost:8000/api/v1/\"","WEB_ROOT":"\"http://localhost:8000\"","VERSION":"\"1.1.16-dev\"","BUILD":"\"5099382fb72e4ce6d6f0f2dd5500568e368b17c3\"","FLUSH_INTERVAL":"10000"}
/home/user/src/facebook/web-extension/node_modules/webpack-dev-server/lib/Server.js:35
const validationErrors = webpack.validateSchema(optionsSchema, options);
^

TypeError: webpack.validateSchema is not a function
at new Server (/home/user/src/facebook/web-extension/node_modules/webpack-dev-server/lib/Server.js:35:36)
at Object. (/home/user/src/facebook/web-extension/dev-server.js:24:16)
at Module._compile (module.js:652:30)
at Object.Module._extensions..js (module.js:663:10)
at Module.load (module.js:565:32)
at tryModuleLoad (module.js:505:12)
at Function.Module._load (module.js:497:3)
at Function.Module.runMain (module.js:693:10)
at startup (bootstrap_node.js:191:16)
at bootstrap_node.js:612:3

[vecna]

sorry for my delay answer, but I use npm start as a way to monitor the file changes, and I never used the dev-server feature. has been implemented by @vrde at the beginning of the project, but I never had a real usage. I can reproduce the bug.