The webpack reported an error. what about cannotresolvemodule ‘fs” net” tls’?

  node.js, question
ERROR in (webpack)-dev-server/~/express/~/send/~/destroy/index.js
 Module not found: Error: Cannot resolve module 'fs' in /home/tigerb/github/easy-vue/node_modules/webpack-dev-server/node_modules/express/node_modules/send/node_modules/destroy
 @ (webpack)-dev-server/~/express/~/send/~/destroy/index.js 14:17-30
 
 ERROR in (webpack)-dev-server/~/sockjs/~/faye-websocket/lib/faye/websocket/client.js
 Module not found: Error: Cannot resolve module 'net' in /home/tigerb/github/easy-vue/node_modules/webpack-dev-server/node_modules/sockjs/node_modules/faye-websocket/lib/faye/websocket
 @ (webpack)-dev-server/~/sockjs/~/faye-websocket/lib/faye/websocket/client.js 2:10-24
 
 ERROR in (webpack)-dev-server/~/sockjs/~/faye-websocket/lib/faye/websocket/client.js
 Module not found: Error: Cannot resolve module 'tls' in /home/tigerb/github/easy-vue/node_modules/webpack-dev-server/node_modules/sockjs/node_modules/faye-websocket/lib/faye/websocket
 @ (webpack)-dev-server/~/sockjs/~/faye-websocket/lib/faye/websocket/client.js 3:10-24

Config

node: {
 fs: "empty"
 bracket

See:webpack wiki