Category Archives: Tutorials

How Node Event Loop REALLY Works: Or Why Most of the Event Loop Diagrams are WRONG

When Bert presented his keynote at Node Interactive Europe 2016 on Event Loop, he started by saying that most of event loops diagrams are WRONG. I’m guilty of using one of them in my talks. :)

This is it. In it, event loop is spinning data back at clients like hot-cakes.

His diagram is closer to the real stuff. In it, event loop starts, works and then quits eventually (pun intended).

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Node.js in Containers Using Docker

Node.js in Containers Using Docker

Container technology is one of the best options for software development and deployment. It allows you to share some of the OS resources while encapsulating the code and other concerns. You can think of containers as virtual machines but with less footprint.

Containers are great for micro services where you replace monoliths with many services. Each of them works in isolation and communicates with other services via a well defined interface (typically REST).

Docker is one of the most popular implementations of containers. Docker’s What is Docker? page has a a neat comparison of containers with VMs. In a nutshell, VMs use hypervisor and each VM has it’s own OS while containers share OS and only separate libraries, bin, executables, etc.

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Autocomplete Widget with React

This project will guide you through building an autocomplete function similar to the one that you might see in Slack (a popular messaging app), as shown in figure 1, when you type something in the search box. For simplicity, our widget will work with room names (the rooms in a chat application).

Figure 1

Figure 1

The autocomplete widget will have (figure 2):

  1. An input field
  2. A list of options filtered according to the entered characters
  3. An Add button (figure 3)
Figure 2

Figure 2

The filtering of the matches will be done using the entered characters as the first characters of the option. In other words, there is a simple comparison that allows us to autocomplete the name of the room (figure X). For example, if you type “mac” and you have “Mac OS X” and “Apple Mac,” then only “Mac OS X” will be shown as a match, not both options.

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React Native Quickly: Start Learning Native iOS Development with JavaScript NOW!

React Native Quickly: Start Learning Native iOS Development with JavaScript

This book is a guide on getting started with React Native for mobile iOS development. You can find source code and the manuscript in https://github.com/azat-co/react-native-quickly. You can read this book online here, or at reactnativequickly.com, or if you prefer videos, you can watch project videos at Node.University: http://node.university/courses/react-native-quickly.

In this book, I’ll introduce you to React Native for native mobile iOS and Android development… and do it quickly. We’ll cover topics such as

  • Why React Native is Awesome
  • Setting up React Native Development for iOS
  • Hello World and the React Native CLI
  • Styles and Flexbox
  • Main React Native UI components
  • Importing Modules into an Xcode Project
  • Project: Timer
  • Project: Weather App

This book is about getting started with React quickly and not about React Native, which is technically a separate library (or some might even call it a framework). But I figured after eight chapters of working with React for web development, it would be fun to apply our knowledge to mobile development by leveraging this awesome library. You’ll be amazed how many React Native skills you already know from React.

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Learn HTTP/2 Server Push by Building Express Middleware

Learn HTTP/2 Server Push by Building Express Middleware

In the previous post, we learned how to perform HTTP/2 server push in a Node server. We also covered the benefits of server push there so to avoid duplication we won’t list them here. We used spdy for server push and H2. But most of the times Node developers don’t work with core HTTP server, they use a framework like Express. So let’s see how we can implement server push in Express.

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Optimize Your App with HTTP/2 Server Push Using Node and Express

Optimize Your App with HTTP/2 Server Push Using Node and Express

HTTP/2 is the new standard of the web. It has many great features which will make the web faster and simplify the development. For example, no need to concatenate files thanks to multiplexing, or a server push which can send files before a browser knows it need them.

This post won’t cover all advantages of HTTP/2. You can read about them online. No need to go into all the details and duplicate text here. Instead, we’ll focus on server push and implement it in Node.js using Express and the spdy library.

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Easy HTTP/2 Server with Node.js and Express.js

Easy HTTP/2 Server with Node.js

The modern Internet with its TCP/IP protocol started around 1975 which is astonishing 41 years ago. For the most part of its existence, we used HTTP and it’s successor HTTP/1.1 (version 1.1) to communicate between clients and servers. It served the web well but the way developers build websites has dramatically changed. There are myriads of external resources, images, CSS files, JavaScript assets. The number of resources is only increasing.

HTTP2 is the first major upgrade to the good old HTTP protocol in over 15 years (first HTTP is circa 1991)! It is optimized for modern websites. The performance is better without complicated hacks like domain sharding (having multiple domains) or file concatenation (having one large file instead of many small ones).

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JSON is Not Cool Anymore: Implementing Protocol Buffers in Node.js

JSON is Not Cool Anymore: Implementing Protocol Buffers in Node.js

There’s a better alternative to the ubiquitous JSON as the communication protocol of the web. It’s Protocol Buffers (protobuf). In a nutshell, protobuf offers a more dense format (faster processing) and provides data schemas (enforcement of structure and better compatibility with old code).

Protocol Buffers were introduced by Google. You can read, more about them at the official Protocol Buffers Developer Guide. For something shorter, read 5 Reasons to Use Protocol Buffers Instead of JSON For Your Next Service which will give you a quick overview of the protobuf benefits over JSON.

The purpose of this article is not to highlight why protobufs are better or sell you on the concept. There are many article online that’ll do it for you. The purpose of this article is to show you how you can get started with this format in the Node.js environment.

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Reactive Web Stack: 3RES – React, Redux, RethinkDB, Express, Socket.io

This post has been written by Scott Hasbrouck. You can find him on Twitter or his website.

It’s been nothing but wonderful to see JavaScript truly catch fire the past few years in web technology, ultimately becoming the most used language in 2016, according to StackOverflow data. My history with JavaScript began about 15 years ago, not all that long after it was first released as part of Netscape Navigator 2, in 1996. My most used learning resource was DynamicDrive, and their tutorials and code snippets of “Dynamic HTML” or DHTML – a term coined by Internet Explorer 4. Really, DHTML was a set of browser features implemented with JavaScript, CSS, and HTML that could get you nifty elements like rollover buttons and stock tickers.

Fasting forward to today, we now live in a world where JavaScript has grown to take over web technology. Not just in the browser, but it is now the most popular backend language according to that same StackOverflow report! Naturally, there are always those who dislike the language citing things like the ease of creating a global variable, or null being an object and undefined being its own datatype. But I’ve found that every language I pick up has quirks that are easily avoidable once you learn to properly use it. And we do want to become experts in our craft and truly learn to master our tools, do we not?

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You Don’t Know Node: Quick Intro to Core Features

You Don't Know Node

This essay was inspired by the Kyle Simpson’s series of books, You Don’t Know JavaScript. They are a good start with JavaScript fundamentals. Node is mostly JavaScript except for a few differences which I’ll highlight in this essay. The code is in the You Don’t Know Node GitHub repository under the code folder.

Why care about Node? Node is JavaScript and JavaScript is almost everywhere! What if the world can be a better place if more developers master Node? Better apps equals better life!

This is a kitchen sink of subjectively the most interesting core features. The key takeaways of this essay are:

  1. Event loop: Brush-up on the core concept which enables non-blocking I/O
  2. Global and process: How to access more info
  3. Event emitters: Crash course in the event-based pattern
  4. Streams and buffers: Effective way to work with data
  5. Clusters: Fork processes like a pro
  6. Handling async errors: AsyncWrap, Domain and uncaughtException
  7. C++ addons: Contributing to the core and writing your own C++ addons

Event Loop

We can start with event loop which is at the core of Node.

Node.js Non-Blocking I/O

Node.js Non-Blocking I/O

It allows processing of other tasks while IO calls are in the process. Think Nginx vs. Apache. It allows Node to be very fast and efficient because blocking I/O is expensive!

Take look at this basic example of a delayed println function in Java:

System.out.println("Step: 1");
System.out.println("Step: 2");
Thread.sleep(1000);
System.out.println("Step: 3");

It’s comparable (but not really) to this Node code:

console.log('Step: 1')
setTimeout(function () {
  console.log('Step: 3')
}, 1000)
console.log('Step: 2')

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