fix(Server): correct node version checks (webpack#1543)

lib/Server.js

@@ -20,6 +20,8 @@ const https = require('https');
 const spdy = require('spdy');
 const sockjs = require('sockjs');
 
+const semver = require('semver');
+
 const killable = require('killable');
 
 const del = require('del');
@@ -46,8 +48,7 @@ const schema = require('./options.json');
 // breaking connection when certificate is not signed with prime256v1
 // change it to auto allows OpenSSL to select the curve automatically
 // See https://github.com/nodejs/node/issues/16196 for more infomation
-const version = parseFloat(process.version.slice(1));
-if (version >= 8.6 && version < 10) {
+if (semver.satisfies(process.version, '8.6.0 - 9')) {
   tls.DEFAULT_ECDH_CURVE = 'auto';
 }
 
@@ -592,7 +593,7 @@ function Server (compiler, options = {}, _log) {
     // - https://github.com/nodejs/node/issues/21665
     // - https://github.com/webpack/webpack-dev-server/issues/1449
     // - https://github.com/expressjs/express/issues/3388
-    if (version >= 10) {
+    if (semver.gte(process.version, '10.0.0')) {
       this.listeningApp = https.createServer(options.https, app);
     } else {
       this.listeningApp = spdy.createServer(options.https, app);

package.json

@@ -44,6 +44,7 @@
     "portfinder": "^1.0.9",
     "schema-utils": "^1.0.0",
     "selfsigned": "^1.9.1",
+    "semver": "^5.6.0",
     "serve-index": "^1.7.2",
     "sockjs": "0.3.19",
     "sockjs-client": "1.3.0",