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Node js express js

  • What do you mean by Express JS and what is its use?
    Express JS is an application framework that is light-weighted node JS. Variety of versatile, helpful and vital options are provided by this JavaScript framework for the event of mobile additionally as internet applications with the assistance of node JS. Express JS Use – Express.js could be a light-weight internet application that helps in organizing the net application into MVC design on the server aspect.
  • Write the steps for setting up an Express JS application?
    Following are the steps accustomed for An Express JS application: A folder with a constant name because the project name is made. A file named package.json is made within the folder created. “npm install” command is run on the electronic communication. It installs all the libraries gift in package.json. A file named server.js is made. “Router” file is made within the package that consists of a folder named index.js. “App” is made within the package that has the index.html file. Let us move on to the next Express JS Interview Questions
  • What function are arguments available to Express JS route handlers?
    The arguments which are available to an Express JS route handler-function are- Req: the request object Res: the response object Next (optional): a function that is employed to pass management to 1 of the following route handlers. The third argument is optional and should be omitted, however, in some cases, it’s helpful wherever there’s a series of handlers and management will be passed to 1 of the following route handlers skipping this one.
  • How to Config properties in Express JS?
    In Express JS, there are 2 ways that for configuring the properties: With process.ENV: A file with the name “.env” is to be created within the project folder. All the properties are to be other within the “.env” file. Any of the properties will be employed in server.js. With require.JS: A file with the name “config.json” is to be created within the config folder within the project folder. The config properties are to be present within the config.json file. Now, ought to be accustomed to access the config.json file.
  • How Should I Structure my Express JS Application?
    This is the basic Express JS Interview Questions asked in an interview. There is no definitive answer to the current question. The solution depends on the dimensions of your application and therefore the team that’s concerned. Routes and alternative application-Express logic will board as several files as you would like, in any directory structure you favor. Read the subsequent examples for inspiration: Route listings Route map MVC vogue controllers Also, there are third-party extensions for Express JS applications that modify a number of these patterns: Resourceful routing
  • How to allow CORS in Express JS? Explain with an example?
    In order to permit CORS in Express.js, add the subsequent code in server.js: For Example: app.all('*', function(req, res, next) { res.set('Access-Control-Allow-Origin', '*'); res.set('Access-Control-Allow-Methods', 'GET, POST, DELETE, PUT'); res.set('Access-Control-Allow-Headers', 'X-Requested-With, Content-Type'); if ('OPTIONS' == req.method) return res.send(200); next(); });
  • How to enable debugging in express app?
    In different operative Systems, we’ve got following commands: On UNIX operating system the command would be as follows: $ DEBUG=express:* node index.js On Windows the command would be: set DEBUG=express:* & node index.js From Webstrome IDE C:\Program Files (x86)\JetBrains\WebStorm 2016.2.4\bin\runnerw.exe" "C:\Program Files\nodejs\node.exe" --debug-brk=61081 --expose_debug_as=v8debug E:\Development\nodejd\librarey\bin\www Let us move on to the next advanced Express JS Interview Questions.
  • Explain Error Handling In Express.js Using An Example?
    From Express 4.0 Error handling is easier. The steps are as following: Create a middleware as following: // error handler app.use(function(err, req, res, next) solely providing error in development res.locals.message = err.message; res.locals.error = req.app.get('env') === 'development' ? err : ; // render the error page res.status(err.status || 500); res.render('error'); }); Install Error Handler Middleware: Install errorhandler npm install errorhandler --save Create a variable var e errorhandler = require('errorhandler') Use the middleware as following: if (process.env.NODE_ENV === 'development') solely use in development app.use(errorhandler()) } function errorNotification(err, str, req) power unit title = 'Error in ' + req.method + ' ' + req.url notifier.notify() }
  • What is the use of next in Express JS?
    Next -It passes management to a consecutive matching route. OR a operate to pass management to 1 of the following route handlers. The argument could also be omitted, however, is beneficial in cases wherever you have got a series of handlers and you’d wish to pass management to 1 of the following route handlers, and skip this one. app.get('/user details/:id?', function(req, res, next)); Req and Res: It represents the request and response objects Next: It passes management to a consecutive matching route.
  • How to Redirect 404 Errors to A Page In ExpressJS?
    In server.js add the subsequent code to send 404 errors back to a page in our ExpressJS App: /* Define fallback route */ app.use(function(req, res, next) { res.status(404).json({errorCode: 404, errorMsg: "route not found"}); });

Overview

What you will learn?

Node.js is a free tool, cross-platform framework running on Mac OS, Windows, and Linux. Node.js course has been intended to help developers to learn and build web applications with the help of JavaScript. Node.js is an event-driven, server-side JavaScript environment that runs JavaScript utilizing the V8 engine developed by Google. The course focuses on different important concepts of Node.js and gives hands-on experience in building HTTP server with Node.js, working with the file system, buffers, stream, events, and multi-processing in Node.js.

What are the requirements?

Training attendees should have total knowledge of JavaScript. If you do not have so you can learn our javascript course because should be easy with web server application design concepts (such as accessing databases and SOA concepts), as well as basic HTML and CSS.

What I am going to get from this course

  • You will understand why server-side JavaScript is useful
  • Install Node.js
  • You will Learn how Node.js is architected to allow high scalability with asynchronous code
  • Create fundamentals of web applications with Node.js
  • Automate tasks with Gulp
  • Build an HTTP server using the core modules in Node.js
  • Use stream I/O to efficiently serve the web pages
  • Create modules to organize the server
  • Test the reliability of the application with unit tests
  • Turn the application to an MVC framework using Express
  • Interface to a MongoDB database and a web service

Target Audience

  • Web developers
  • DevOps engineers
  • Data Scientists
  • Game developers

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