npm the package manager npm is a couple of things. First and foremost, it is an online repository for the publishing of open-source Node.js projects. Second, it is a CLI tool that aids you install those packages and manage their versions and dependencies. There are hundreds of thousands of Node.js libraries and applications on npm …
== and === in JavaScript
The equality operator in javascript is used to compare if two values are equal. The comparison is made by == and === operators in javascript. The main difference between the == and === operator in javascript is that the == operator does the type conversion of the operands before comparison, whereas the === operator compares the values as well as the data types of the operands. The == and != operators in javascript …
Node / Express: EADDRINUSE, Address already in use – Kill server
Locate the process: Kill the specific process:
What are express.json() and express.urlencoded()
What is Middleware? It is those methods/functions/operations that are called BETWEEN processing the Request and sending the Response in your application method. When talking about express.json() and express.urlencoded() think specifically about POST requests (i.e. the .post request object) and PUT Requests (i.e. the .put request object) You DO NOT NEED express.json() and express.urlencoded() for GET Requests or DELETE Requests. You NEED express.json() and express.urlencoded() for POST and …
Continue reading “What are express.json() and express.urlencoded()”
map() and forEach() in Javascript
The main difference between map and forEach is that the map method returns a new array by applying the callback function on each element of an array, while the forEach method doesn’t return anything.
How to update Node.js
1. Check the current version node -v 2. nstall n package using npm if you do not have it installed yet. sudo npm install -g n 3. Then, you can update your Node.js to the version you want. sudo n stable
How to Install Node.js and npm on Windows
Go to Node.js website and download Node.js. Choose the option to install Node.js and npm. When the install finished, check the result in command line:
Some notes on CRUD application – Node.js, Express.js & MongoDB
CRUD – READ In Express, we handle a GET request with the get method: app.get(endpoint, callback) endpoint is the requested endpoint. It’s the value that comes after your domain name. Here are some examples: When you visit localhost:3000, you’re actually visiting localhost:3000/. In this case, browsers requested for /. You’re reading this article on https://zellwk.com/blog/crud-express-mongodb/. …
Continue reading “Some notes on CRUD application – Node.js, Express.js & MongoDB”
Building a functional chat app based on Node.js (2)
Web Sockets Web Sockets are a much more responsive technology, since they keep a connection directly open at all times for each client. This allows either the client or server to directly notify each other when changes occur on their side. In contrast to the request / response model, the server does not wait for …
Continue reading “Building a functional chat app based on Node.js (2)”
Building a functional chat app based on Node.js (1)
Introduction We’ll use our new NodeJS knowledge to build a realistic web server that handles the backend of a messaging app for realtime chatting. We will also create a minimal front end so we can see the service working. These skills will be very applicable to those of you who are creating a web app …
Continue reading “Building a functional chat app based on Node.js (1)”