Decompose bind to init and listen

Refs: #455
PR-URL: #459

Author: tshemsedinov

lib/server.js

@@ -154,9 +154,8 @@ const addHeaders = ({ origin }) => {
   if (origin) HEADERS['Access-Control-Allow-Origin'] = origin;
 };
 
-class Server extends EventEmitter {
+class Server {
   constructor(application, options) {
-    super();
     this.retry = options.retry ?? DEFAULT_LISTEN_RETRY;
     this.application = application;
     this.options = options;
@@ -166,20 +165,15 @@ class Server extends EventEmitter {
     this.httpServer = null;
     this.wsServer = null;
     this.clients = new Set();
-    this.bind();
+    this.init();
   }
 
-  bind() {
-    const { application, console, balancer } = this;
-    const { host, port, protocol, timeouts, nagle = true } = this.options;
-    const { key, cert, SNICallback } = this.options;
+  init() {
+    const { application, balancer, options } = this;
+    const { protocol, nagle = true, key, cert, SNICallback } = options;
     const proto = protocol === 'http' || balancer ? http : https;
-    const options = { key, cert, noDelay: !nagle, SNICallback };
-    this.httpServer = proto.createServer(options);
-
-    this.httpServer.on('listening', () => {
-      console.info(`Listen port ${port}`);
-    });
+    const opt = { key, cert, noDelay: !nagle, SNICallback };
+    this.httpServer = proto.createServer(opt);
 
     this.httpServer.on('request', async (req, res) => {
       const transport = new HttpTransport(this, req, res);
@@ -212,18 +206,30 @@ class Server extends EventEmitter {
         else this.message(client, data);
       });
     });
+  }
 
-    this.wsServer.on('error', (err) => {
-      if (err.code !== 'EADDRINUSE') return;
-      this.retry--;
-      if (this.retry === 0) return void this.emit('error', err);
-      console.warn(`Address in use: ${host}:${port}, retry...`);
-      setTimeout(() => {
-        this.bind();
-      }, timeouts.bind);
-    });
+  listen() {
+    const { console, options } = this;
+    const { host, port, timeouts } = options;
 
-    this.httpServer.listen(port, host);
+    return new Promise((resolve, reject) => {
+      this.httpServer.on('listening', () => {
+        console.info(`Listen port ${port}`);
+        resolve(this);
+      });
+
+      this.wsServer.on('error', (err) => {
+        if (err.code !== 'EADDRINUSE') return;
+        this.retry--;
+        if (this.retry === 0) return void reject(err);
+        console.warn(`Address in use: ${host}:${port}, retry...`);
+        setTimeout(() => {
+          this.httpServer.listen(port, host);
+        }, timeouts.bind);
+      });
+
+      this.httpServer.listen(port, host);
+    });
   }
 
   message(client, data) {

metacom.d.ts

@@ -142,7 +142,8 @@ export class Server {
   wsServer: any;
   clients: Set<Client>;
   constructor(options: Options, application: object);
-  bind(): void;
+  init(): void;
+  listen(): Promise<void>;
   message(client: Client, data: string): void;
   rpc(client: Client, packet: CallPacket): Promise<void>;
   binary(client: Client, data: Buffer): void;