smali

smali

воскресенье, 13 сентября 2015 г.

Overview of the JavaScript ecosystem

What can I accomplish with Javascript?

The ecosystem of JavaScript has grown. Long gone are the days of simply inserting jQuery into your website and fading stuff in or out.
Entering the world of JavaScript today is an overwhelming task with lots of possibilities. It also means that it’s a world that’s brimming with opportunity. In the words of Jeff Atwood (http://blog.codinghorror.com/the-principle-of-least-power/):
Any application that can be written in JavaScript, will eventually be written in JavaScript.

The different aspects of JavaScript

There was never a better time to find a niche within the JavaScript ecosystem. Here’s a list of aspects you can dive into and which this articlewill explore deeper:
  1. Front-end development
  2. Command line interface (CLI) applications
  3. Desktop (GUI) applications
  4. Mobile applications
  5. Back-end development
  6. Any combination of the above

Front-end development

Developing the user facing part of websites has become increasingly complex by becoming highly interactive and offloading traditional server-side tasks to the front-end. It was once unfathomable that we’ll be running the likes of Google Maps, Spotify or YouTube in our web browsers but here we are, with a varied toolset to make complex web applications.
Front-end web development has grown exponentially in the last few years and I’ll offer just a glimpse of that here.

The basics of front-end web development

For a long time, JavaScript has been used solely for DOM manipulation with the odd animation thrown in for good measure. Since the beginnings, there was a big discrepancy between browser features.
jQuery started a revolution with abstracting the aforementioned browser features and making DOM manipulation easy while also bringing quite a few utilities to the table.
Nowadays, it’s quite easy to manipulate the DOM with pure JavaScript and there’s a very nice cheat sheet just for that purpose.

Efficiency through frameworks

With the growing complexity of websites and websites growing to web applications, there was a need to address the complex issues of web applications (state handling, data binding, view rendering, etc.). Many frameworks rose to that challenge and two that are probably most popular today are AngularJS and React.
It’s clear that Angular and React gained such traction since the former is backed by Google and the latter by Facebook. While Angular contains the whole MVC paradigm, React is somewhat leaner and mostly considered the V of MVC.
New frameworks show up all the time and time will only tell which one will reign supreme (of course, if something like that even happens).

What’s in a name?

There’s a good chance that you won’t be using JavaScript any more, but any of the languages that transpile to JavaScript like:
  • EcmaScript 6 — the newest spec of JavaScript
  • TypeScript — Microsoft’s superset of JavaScript featuring types
Apart from just adding new features to a language, there’s a good chance you’ll be modularising your application by using ES6 native modules orCommonJS (mostly for Node.js developmentor RequireJS (async module loading mostly for websites).
Transpilation and connecting of modularised applications is done via build tools (Gulp and Grunt, mentioned in detail later), using transpile tools (likeBabel or Traceur) and module builders (like Browserify or Webpack). You’ll most likely transpile and build your modules in every aspect of JavaScript development.
There is a boatload of tools that weren’t mentioned. It is left to the reader to explore them and a good starting place is the awesome list of front-end development.

Command line interface (CLI) applications

Gulp running a gulpfile
Many developers rely mostly on the CLI in their day-to-day development — be it code linting, task running or starting a server, there’s a certain beauty in the efficiency of executing a task purely from the command line.
CLI applications are written using Node.js (or io.js, a fork of Node.js which is going to be merged back into Node.js soon). Node.js is an open source, cross-platform runtime environment that allows you to execute your JavaScript code everywhere through Chrome’s JavaScript runtime (not just in the browser, like before). In essence, once someone installs Node.js and takes your CLI application (package), it can be executed.

Package managers

It would be really bad if you’d have to write every functionality of every app from scratch. That’s where npm steps in. npm is a package manager forNode.js modules and using packages is really simple — install and require them.
The CLI application that you write can also be packaged as a Node.js module and distributed via npm. That is the preferred way of getting your CLI application (or Node.js modules for that matter) to other people.
Many popular libraries and tools have CLI applications for easier use likeGulp or Grunt. There’s also a list of awesome Node.js CLI apps.

Build tools

Build tools (and task runners) get a special mention because they’re the most basic tools you’ll be using no matter what type of application you’re building.
The most popular build tools nowadays are Grunt and Gulp which make the process of transforming your code to something usable much easier. A typical scenario is to:
  • transpile your JavaScript from EcmaScript 6 to EcmaScript 5
  • compile your SCSS to CSS
  • minify and concatenate the resulting files
  • copy everything to a distribution folder

Desktop (GUI) applications

Slack
Applications are mostly moving to the web or onto mobile devices. Still, desktop applications offer an immersion mostly unavailable to web applications.
The biggest advantage of writing your desktop applications with JavaScript is abstraction of the platform for which you are coding. Your applications are cross-platform and the modules you use simplify the usage of typical desktop features (such as tray icons, notifications, global keyboard shortcuts, etc.).
Having a good project structure allows you a lot of code reuse between your web and desktop application. That in turn leads to easier maintenance.

Available tools

There are two popular projects which allow you to write a desktop application via HTML/JS:
  • NW.js — formerly known as node-webkit, it’s the most popular way of writing native desktop applications
  • Electron — a newer contender made by GitHub which already gained big traction in the same space

Notable applications

Both of the mentioned projects are used in quite a few popular desktop applications.
Notable applications done with NW.js or Electron include Slack, Game Dev Tycoon, GitHub Atom, WhatsApp Desktop, Facebook Messenger Desktop, Popcorn Time and Microsoft Visual Studio Code. There’s an extensive list of projects made with NW.js and an extensive list of projects made withElectron (both containing links to Repositories for learning or contributing purposes).

Mobile applications

Facebook Mobile applications made with React Native
With such a booming market, it makes sense to develop mobile applications. The JavaScript ecosystem provides a few solutions to developing cross-platform (iOS, Android and Windows Phone) applications. The most popular projects providing cross-platform mobile application include:
Ionic and Phonegap use a browser wrapper around your HTML/JS and provide access to otherwise unavailable features of the platform (camera, various sensors, etc.). Ionic is leveraging the power of Angular to provide a well-tested and stable platform.
Facebook’s React Native has an interesting approach in which they render your written application to higher-level platform-specific components to achieve a truly native look of the app. This means that you’ll have to write a separate view layer for each platform but you’ll do it in a consistent manner.In the words of Tom Occhino, a software engineer at Facebook, they’re trying the approach of “learn once, write anywhere” which is completely in the spirit of such a diverse ecosystem as this one.

Notable applications

While React Native doesn’t support Android just yet, it’s great that Facebook is using it in their own apps already (Facebook Groups and Facebook Ads Manager). Android support should arrive in less than two months.
Mobile applications written in Ionic or Phonegap include popular applications such as Sworkit, Mallzee, Chefsteps, Snowbuddy and Rormix. There are extensive lists of applications built with Ionic and applications built with Phonegap.

Back-end development

Node.js is also the main driving force in back-end development in JavaScript.
The main advantage of Node.js is it’s event-driven, non-blocking I/O model. That said — Node.js is great at handling data-intensive real-time applications with many concurrent requests. Node.js does it by handling all these concurrent requests on a single thread and thereby greatly reducing needed system resources and allowing for great scalability.
A typical example for these benefits are chat applications. They require uninterrupted connections from clients to a chat room (real-time, non-blocking) and notifications of new messages (event-driven) where you’re supposed to support large numbers of clients and rooms (data-intensive).
You can also have a fairly decent web server written in JavaScript. The main takeaway here is that its main purpose shouldn’t be CPU intensive tasks or connections to a relational database, but a high volume of connections.
The most popular modules associated with back-end development are:
  • express — simple web framework for Node.js
  • socket.io — module for building real-time web applications
  • forever — module for ensuring that a given Node.js script runs continously

How these modules fit together

First of all, you need a web server which can process typical HTTP request on various routes like http://localhost:3000/about. That’s where express comes in.
To have an uninterrupted connection with the server, socket.io is used with a server-side and client-side component of establishing connections.
Since express runs on one thread, we must ensure that an exception doesn’t stop the process (and server altogether). For that purposes, we use forever.
To learn more about these modules, visit their respective websites which feature many tutorials (socket.io even has you building a chat server and client as a hello world application).

Any combination of the above


Meteor JavaScript app platform
It’s easy to imagine how all these aspects come together.
One of the most popular way of combining them is having a full-stack JavaScript framework like MEAN or Meteor.
MEAN combines express, Angular, Node.js and MongoDB to offer a web platform whose back-end as well as front-end are written in JavaScript.
Meteor is a platform offering full-stack web and mobile application development in JavaScript.
Another example could be a JavaScript minifier for which you write the base module for Node.js and then use that module in a CLI application, a desktop application, a mobile application and a web application (served by express, of course) — all in JavaScript.
The possibilities are endless and we’re probably just scratching the surface. This ecosystem is exploding with new techniques, frameworks, modules and even language specs being defined all the time. It’s really exciting.

Where should I start?

That depends on how familiar with JavaScript you are right now.
Should you only be starting out, there are great resources to start with JavaScript (or programming, for that matter) like CodecademyNodeschoolor Codeschool which are all interactive and fun.
If you’ve got some jQuery knowledge under your belt and have been dabbling with pure JavaScript, know that no framework or library is ever going to replace a good understanding of core JavaScript. Start with really digging into the nitty-gritty of JavaScript. For that purpose, I can’t recommend Kyle Simpson’s You don’t know JS series enough. It’s open source and available on GitHub. The open source nature makes it really easy for you to contribute with errors you notice in the books. The books are also available as hard copies if you prefer reading that way with the added benefit of supporting the author.
With a strong JavaScript core, it would be wise to brush up on Node.js. As you’ve seen, it’s the basis for almost all of the aspects. Node.js promotes asynchronous programming which takes a while to get accustomed to but solves the problem of blocking UI. The aforementioned learning sources (Nodeschool and Codeschool) can also be used here.
After that, just follow the path that seems the most interesting. Chances are, you’ll fall deeper down the rabbit hole, discover new things and enjoy the experience even more.

Комментариев нет:

Отправить комментарий