add error event

index.js

@@ -6,8 +6,8 @@ const zlib = require('zlib');
 const url = require('url');
 const fs = require('fs');
 
-const PORT = process.env.PORT || process.argv[3] || 3000;
 const baseDir = process.env.DIR || path.resolve(process.argv[2] || '.');
+const PORT = process.env.PORT || process.argv[3] || 3000;
 
 const maxAge = 60 * 60 * 24 * 365; // 1 year
 const gzipTypes = /(?:html|css|js|xml)/ig;
@@ -28,15 +28,17 @@ const mimeTypes = {
 };
 
 const app = http.createServer((req, res) => {
-  if (req.method !== 'GET' && req.method !== 'HEAD') {
-    // method not allowed
-    res.writeHead(405, 'Method Not Allowed', {'Allow': 'GET, HEAD', 'Content-Length': '0'});
+  if (req.method !== 'GET' && req.method !== 'HEAD') { // method not allowed
+    res.writeHead(405, 'Method Not Allowed', {'Allow': 'GET, HEAD', 'Content-Length': 0});
     return res.end();
   }
 
   sendFile(req, res, url.parse(req.url).pathname);
 });
 
+/**
+ * Send file
+ */
 function sendFile(req, res, pathname) {
   let filename = path.join(baseDir, unescape(pathname));
 
@@ -55,7 +57,7 @@ function sendFile(req, res, pathname) {
         return sendFile(req, res, path.join(pathname, 'index.html'));
       }
 
-      var lastModified = stat.mtime.toUTCString();
+      let lastModified = stat.mtime.toUTCString();
       res.setHeader('Last-Modified', lastModified);
 
       let expires = new Date();
@@ -87,10 +89,51 @@ function sendFile(req, res, pathname) {
   });
 }
 
+app.on('error', onError);
+app.on('listening', onListening);
+
 module.exports.app = app;
 
 module.exports.listen = _ => {
-  app.listen(PORT, _ => {
-    console.log(`Server running at http://localhost:${PORT}/`);
-  });
+  app.listen(PORT, '0.0.0.0');
 };
+
+
+/**
+ * Event listener for HTTP server "error" event.
+ */
+function onError(error) {
+  if (error.syscall !== 'listen') {
+    throw error;
+  }
+
+  let bind = typeof port === 'string'
+    ? 'Pipe ' + port
+    : 'Port ' + port;
+
+  // handle specific listen errors with friendly messages
+  switch (error.code) {
+    case 'EACCES':
+      console.error(`${bind} requires elevated privileges`);
+      process.exit(1);
+      break;
+    case 'EADDRINUSE':
+      console.error(`${bind} is already in use`);
+      process.exit(1);
+      break;
+    default:
+      throw error;
+  }
+}
+
+/**
+ * Event listener for HTTP server "listening" event.
+ */
+function onListening() {
+  let addr = app.address();
+  let bind = typeof addr === 'string'
+    ? 'pipe ' + addr
+    : 'port ' + addr.port;
+
+  console.log(`Server listening on ${bind}`);
+}