refactor: moved out callback to dedicated files

server/src/app.ts

@@ -1,16 +1,22 @@
 import path from 'path'
-
 import http from 'http'
+
 import express, { Application } from 'express'
 import cookieParser from 'cookie-parser'
 import logger from 'morgan'
-import debug0 from 'debug'
+import initDebug from 'debug'
+
 import indexRouter from './routes'
 import usersRouter from './routes/users'
 
-const ROOT_DIR = path.resolve('../')
+import { normalizePort } from './helpers/port'
+import { getErrorCb, getListeningCb } from './helpers/server-callbacks'
 
+const ROOT_DIR = path.resolve('../')
+const PORT = normalizePort(process.env.PORT || '6595')
+const debug = initDebug('deemix-gui:server')
 const app: Application = express()
+const server = http.createServer(app)
 
 app.use(logger('dev'))
 app.use(express.json())
@@ -21,89 +27,8 @@ app.use(express.static(path.join(ROOT_DIR, 'webui', 'public')))
 app.use('/', indexRouter)
 app.use('/users', usersRouter)
 
-/**
- * Module dependencies.
- */
+app.set('port', PORT)
 
-const debug = debug0('deemix-gui:server')
-/**
- * Get port from environment and store in Express.
- */
-
-const port = normalizePort(process.env.PORT || '3000')
-app.set('port', port)
-
-/**
- * Create HTTP server.
- */
-
-const server = http.createServer(app)
-
-/**
- * Listen on provided port, on all network interfaces.
- */
-
-server.listen(port)
-server.on('error', onError)
-server.on('listening', onListening)
-
-/**
- * Normalize a port into a number, string, or false.
- */
-
-function normalizePort (val:string) {
-  const port = parseInt(val, 10)
-
-  if (isNaN(port)) {
-    // named pipe
-    return val
-  }
-
-  if (port >= 0) {
-    // port number
-    return port
-  }
-
-  return false
-}
-
-/**
- * Event listener for HTTP server "error" event.
- */
-
-function onError (error: any) {
-  if (error.syscall !== 'listen') {
-    throw error
-  }
-
-  const 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)
-    case 'EADDRINUSE':
-      console.error(bind + ' is already in use')
-      process.exit(1)
-    default:
-      throw error
-  }
-}
-
-/**
- * Event listener for HTTP server "listening" event.
- */
-
-function onListening () {
-  const addr = server.address()
-
-  if (addr) {
-    const bind = typeof addr === 'string'
-      ? 'pipe ' + addr
-      : 'port ' + addr.port
-    debug('Listening on ' + bind)
-  }
-}
+server.listen(PORT)
+server.on('error', getErrorCb(PORT))
+server.on('listening', getListeningCb(server, debug))

server/src/helpers/port.ts

@@ -0,0 +1,19 @@
+/**
+ * Normalize a port into a number, string, or false.
+ */
+
+export function normalizePort (portString:string) {
+  const port = parseInt(portString, 10)
+
+  if (isNaN(port)) {
+    // named pipe
+    return portString
+  }
+
+  if (port >= 0) {
+    // port number
+    return port
+  }
+
+  return false
+}

server/src/helpers/server-callbacks.ts

@@ -0,0 +1,47 @@
+import http from 'http'
+import type { Debugger } from 'debug'
+
+/**
+ * Event listener for HTTP server "error" event.
+ */
+export function getErrorCb (port: number | string | boolean) {
+  return (error: any) => {
+    if (error.syscall !== 'listen') {
+      throw error
+    }
+
+    const 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)
+      }
+      case 'EADDRINUSE': {
+        console.error(bind + ' is already in use')
+        process.exit(1)
+      }
+      default:
+        throw error
+    }
+  }
+}
+
+/**
+ * Event listener for HTTP server "listening" event.
+ */
+export function getListeningCb (server: http.Server, debug: Debugger) {
+  return () => {
+    const addr = server.address()
+
+    if (addr) {
+      const bind = typeof addr === 'string'
+        ? 'pipe ' + addr
+        : 'port ' + addr.port
+      debug('Listening on ' + bind)
+    }
+  }
+}