launch https websocket server is --https (#708)

src/Bundler.js

@@ -78,6 +78,7 @@ class Bundler extends EventEmitter {
       minify:
         typeof options.minify === 'boolean' ? options.minify : isProduction,
       hmr: typeof options.hmr === 'boolean' ? options.hmr : watch,
+      https: options.https || false,
       logLevel: typeof options.logLevel === 'number' ? options.logLevel : 3,
       mainFile: this.mainFile,
       hmrPort: options.hmrPort || 0,
@@ -248,7 +249,7 @@ class Bundler extends EventEmitter {
 
     if (this.options.hmr) {
       this.hmr = new HMRServer();
-      this.options.hmrPort = await this.hmr.start(this.options.hmrPort);
+      this.options.hmrPort = await this.hmr.start(this.options);
     }
 
     this.farm = WorkerFarm.getShared(this.options);

src/HMRServer.js

@@ -1,11 +1,19 @@
+const http = require('http');
+const https = require('https');
 const WebSocket = require('ws');
 const prettyError = require('./utils/prettyError');
+const generateCertificate = require('./utils/generateCertificate');
 const logger = require('./Logger');
 
 class HMRServer {
-  async start(port) {
+  async start(options = {}) {
     await new Promise(resolve => {
-      this.wss = new WebSocket.Server({port}, resolve);
+      let server = options.https
+        ? https.createServer(generateCertificate(options))
+        : http.createServer();
+
+      this.wss = new WebSocket.Server({server});
+      server.listen(options.hmrPort, resolve);
     });
 
     this.wss.on('connection', ws => {

src/builtins/hmr-runtime.js

@@ -16,7 +16,8 @@ module.bundle.Module = Module;
 
 if (!module.bundle.parent && typeof WebSocket !== 'undefined') {
   var hostname = process.env.HMR_HOSTNAME || location.hostname;
-  var ws = new WebSocket('ws://' + hostname + ':' + process.env.HMR_PORT + '/');
+  var protocol = window.location.protocol === 'https:' ? 'wss' : 'ws';
+  var ws = new WebSocket(protocol + '://' + hostname + ':' + process.env.HMR_PORT + '/');
   ws.onmessage = function(event) {
     var data = JSON.parse(event.data);