Category Archives: JavaScript

ES 7 and ES8 Features

Recently I wrote a blog post and even created an online course on ES6/ES2015. Guess what? TC39—the mighty overseer of JavaScript—is moving forward with ES8 so let’s cover ES7 and ES8 (or ES2016 and ES2017 officially). Luckily, they are much, much, much smaller than the best of a standard that was ES6. Really! ES7 has only two (2) features!

ES7 features:

  1. Array.prototype.includes
  2. Exponentiation Operator

ES8 is not finalized yet as of this writing (Jan, 2017) but we can assume all finished proposals (stage 4) and most of stage 3 (more on stages here and in my course). The finished 2017 (ES8) proposals are:

  1. Object.values/Object.entries
  2. String padding
  3. Object.getOwnPropertyDescriptors
  4. Trailing commas in function parameter lists and calls
  5. Async Functions

I won’t include stage 3 proposals in this post, but you can check the status of proposals from stage 1 to 3 here.

Let’s dive deeper into the proposals and features…

The rest of the article:


Preact: Fast 3kB alternative to React with the same ES6 API.

Preact is a lightweight (just 3kb) alternative to React which has same interface (ES6), but better performance. Preact also has a few new features, i.e.,

  • Arguments props, state and context are passed to render()
  • Standard HTML attributes class and for
  • React DevTools right out of the box

There is a migration guide at the which is basically replacing react and react-dom with preact npm packages.

I imported my AnalogDisplay component (original in React) into preact JSFiddle code, and they worked well. I can either use this.state or just state in render(). Here’s the JSFiddle code: and the source code:

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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 You can read this book online here, or at, or if you prefer videos, you can watch project videos at Node.University:

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

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");
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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Meeting React.js: An Excerpt from ‘React Quickly’

React Quickly Menu

This is an excerpt from React Quickly (Manning, 2016). You can download the entire first chapter for free at Manning. The book is scheduled for release in the first quarter of 2016, but MEAP is available right now. Use code “mardandz” to get 39% off.

Each chapter has a project which is supplemented by a video screencast hosted on YouTube.

React Quickly Screencasts

React Quickly Screencasts

Project: Menu with React.js

The project for this article will be minimal. The idea is to have a dynamically generated menu which will consist of <a> tags.

We’ll use custom React components Menu and Link. They way we create them is similar to the way we create the HelloWorld component in the previous example. The project will show you how to render nested elements programmatically. In the previous examples, we just coded the children manually. We’ll use the map() function for it.

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React Quickly Screencasts

Each chapter of my new book React Quickly (Manning, 2016) has a project which is supplemented by a video screencast. Watch the videos here or on YouTube. The code is on GitHub.

React Quickly

React Quickly

Also, you can download the entire first chapter for FREE at Manning. The book is scheduled for release in the first quarter of 2016, but early access (e-copy) is available right now. Use code “mardandz” to get 39% off at Manning.

React Quickly Chapter 1 Project: Menu with React:

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Full Stack JavaScript

My new book Full Stack JavaScript (my 4th traditionally-published book) comes with a series of screencast videos for better immersion in a wonderful and mesmerizing world of Node.js, Backbone and MongoDB. It’s a one thing to read through the text and another to follow up with dynamic videos which walk you through the book’s projects.

Full Stack JavaScript

Full Stack JavaScript

The videos and the source code are open source, meaning they are publicly available. Therefore, you don’t have to buy a book—you can just watch the 14 videos on YouTube (playlist) and go through the code on GitHub (repository).

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React for Fun and Profit

React is a fun little library for User Interfaces. You can use it for web, or mobile development. It’s fun because it’s very developer-friendly. You write your code in the same place without having to switch between HTML and JavaScript files.

I’ve heard many times people complaining about React’s favorite syntax JSX. I found it great, after I spent a few hours learning and coding with it. Contrary to what people unfamiliar with React think, JSX is not HTML in JavaScript. JSX is just an XML-like syntax which produces JavaScript. There’s not HTML involved at this step. When you develop with React, you write JavaScript objects. Later React automagically transforms those object into rendered HTML.

Also, React is very fast due to its virtual DOM and smart diffing algorithm. And React’s component approach to architecture allows for great development scalability. Just ask Facebook, Twitter, Slack and other companies with large web apps.

Furthermore, you can use React with React Native to create native iOS and Android apps. These apps can share the same code. It’s not the same as the so called hybrid or HTML5 apps. The latter are websites trapped into a headless browser in a mobile app. The former is a real native app which uses JavaScript interface for it’s UIs and logic.

Hey, you can even use live reloading when developing apps with React Native. Pure joy! The feature native mobile developers can only dream of! “React is fun, but show me the money”— you can yell. Fair enough.

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