discard prettier changes

en/guide/migrating-4.md

@@ -101,8 +101,8 @@ In version 4 you can use a variable parameter to define the path where middlewar
 For example:
 
 ```js
-app.use("/book/:id", (req, res, next) => {
-  console.log("ID:", req.params.id);
+app.use('/book/:id', (req, res, next) => {
+  console.log('ID:', req.params.id);
   next();
 });
 ```
@@ -133,15 +133,15 @@ Here is an example of chained route handlers that are defined by using the `app.
 
 ```js
 app
-  .route("/book")
+  .route('/book')
   .get((req, res) => {
-    res.send("Get a random book");
+    res.send('Get a random book');
   })
   .post((req, res) => {
-    res.send("Add a book");
+    res.send('Add a book');
   })
   .put((req, res) => {
-    res.send("Update the book");
+    res.send('Update the book');
   });
 ```
 
@@ -159,21 +159,21 @@ For example, create a router file named `birds.js` in the app directory,
 with the following content:
 
 ```js
-var express = require("express");
+var express = require('express');
 var router = express.Router();
 
 // middleware specific to this router
 router.use((req, res, next) => {
-  console.log("Time: ", Date.now());
+  console.log('Time: ', Date.now());
   next();
 });
 // define the home page route
-router.get("/", (req, res) => {
-  res.send("Birds home page");
+router.get('/', (req, res) => {
+  res.send('Birds home page');
 });
 // define the about route
-router.get("/about", (req, res) => {
-  res.send("About birds");
+router.get('/about', (req, res) => {
+  res.send('About birds');
 });
 
 module.exports = router;
@@ -182,11 +182,11 @@ module.exports = router;
 Then, load the router module in the app:
 
 ```js
-var birds = require("./birds");
+var birds = require('./birds');
 
 // ...
 
-app.use("/birds", birds);
+app.use('/birds', birds);
 ```
 
 The app will now be able to handle requests to the `/birds` and
@@ -326,36 +326,36 @@ Version 3 app
 Consider an Express v.3 application with the following `app.js` file:
 
 ```js
-var express = require("express");
-var routes = require("./routes");
-var user = require("./routes/user");
-var http = require("http");
-var path = require("path");
+var express = require('express');
+var routes = require('./routes');
+var user = require('./routes/user');
+var http = require('http');
+var path = require('path');
 
 var app = express();
 
 // all environments
-app.set("port", process.env.PORT || 3000);
-app.set("views", path.join(__dirname, "views"));
-app.set("view engine", "pug");
+app.set('port', process.env.PORT || 3000);
+app.set('views', path.join(__dirname, 'views'));
+app.set('view engine', 'pug');
 app.use(express.favicon());
-app.use(express.logger("dev"));
+app.use(express.logger('dev'));
 app.use(express.methodOverride());
-app.use(express.session({ secret: "your secret here" }));
+app.use(express.session({ secret: 'your secret here' }));
 app.use(express.bodyParser());
 app.use(app.router);
-app.use(express.static(path.join(__dirname, "public")));
+app.use(express.static(path.join(__dirname, 'public')));
 
 // development only
-if (app.get("env") === "development") {
+if (app.get('env') === 'development') {
   app.use(express.errorHandler());
 }
 
-app.get("/", routes.index);
-app.get("/users", user.list);
+app.get('/', routes.index);
+app.get('/users', user.list);
 
-http.createServer(app).listen(app.get("port"), () => {
-  console.log("Express server listening on port " + app.get("port"));
+http.createServer(app).listen(app.get('port'), () => {
+  console.log('Express server listening on port ' + app.get('port'));
 });
 ```
 
@@ -440,61 +440,61 @@ Then, remove invalid code, load the required middleware, and make other
 changes as necessary. The `app.js` file will look like this:
 
 ```js
-var http = require("http");
-var express = require("express");
-var routes = require("./routes");
-var user = require("./routes/user");
-var path = require("path");
-
-var favicon = require("serve-favicon");
-var logger = require("morgan");
-var methodOverride = require("method-override");
-var session = require("express-session");
-var bodyParser = require("body-parser");
-var multer = require("multer");
-var errorHandler = require("errorhandler");
+var http = require('http');
+var express = require('express');
+var routes = require('./routes');
+var user = require('./routes/user');
+var path = require('path');
+
+var favicon = require('serve-favicon');
+var logger = require('morgan');
+var methodOverride = require('method-override');
+var session = require('express-session');
+var bodyParser = require('body-parser');
+var multer = require('multer');
+var errorHandler = require('errorhandler');
 
 var app = express();
 
 // all environments
-app.set("port", process.env.PORT || 3000);
-app.set("views", path.join(__dirname, "views"));
-app.set("view engine", "pug");
-app.use(favicon(path.join(__dirname, "/public/favicon.ico")));
-app.use(logger("dev"));
+app.set('port', process.env.PORT || 3000);
+app.set('views', path.join(__dirname, 'views'));
+app.set('view engine', 'pug');
+app.use(favicon(path.join(__dirname, '/public/favicon.ico')));
+app.use(logger('dev'));
 app.use(methodOverride());
 app.use(
   session({
     resave: true,
     saveUninitialized: true,
-    secret: "uwotm8",
+    secret: 'uwotm8',
   })
 );
 app.use(bodyParser.json());
 app.use(bodyParser.urlencoded({ extended: true }));
 app.use(multer());
-app.use(express.static(path.join(__dirname, "public")));
+app.use(express.static(path.join(__dirname, 'public')));
 
-app.get("/", routes.index);
-app.get("/users", user.list);
+app.get('/', routes.index);
+app.get('/users', user.list);
 
 // error handling middleware should be loaded after the loading the routes
-if (app.get("env") === "development") {
+if (app.get('env') === 'development') {
   app.use(errorHandler());
 }
 
 var server = http.createServer(app);
-server.listen(app.get("port"), () => {
-  console.log("Express server listening on port " + app.get("port"));
+server.listen(app.get('port'), () => {
+  console.log('Express server listening on port ' + app.get('port'));
 });
 ```
 
 <div class="doc-box doc-info" markdown="1">
 Unless you need to work directly with the `http` module (socket.io/SPDY/HTTPS), loading it is not required, and the app can be simply started this way:
 
 ```js
-app.listen(app.get("port"), () => {
-  console.log("Express server listening on port " + app.get("port"));
+app.listen(app.get('port'), () => {
+  console.log('Express server listening on port ' + app.get('port'));
 });
 ```
 
@@ -595,17 +595,17 @@ delete the line that says `module.exports = app;` at the end of the
 `app.js` file, then paste the following code in its place:
 
 ```js
-app.set("port", process.env.PORT || 3000);
+app.set('port', process.env.PORT || 3000);
 
-var server = app.listen(app.get("port"), () => {
-  debug("Express server listening on port " + server.address().port);
+var server = app.listen(app.get('port'), () => {
+  debug('Express server listening on port ' + server.address().port);
 });
 ```
 
 Ensure that you load the `debug` module at the top of the `app.js` file by using the following code:
 
 ```js
-var debug = require("debug")("app4");
+var debug = require('debug')('app4');
 ```
 
 Next, change `"start": "node ./bin/www"` in the `package.json` file to `"start": "node app.js"`.