Book Image

Getting Started with NativeScript

By : Nathanael J. Anderson
Book Image

Getting Started with NativeScript

By: Nathanael J. Anderson

Overview of this book

NativeScript allows you to build a fast cross-platform application that has a native UI. NativeScript is a true cross-platform framework that generates native speed applications using the native components of the host platform, all using JavaScript. Although NativeScript allows you to build your application in JavaScript, you have full access to the host OS from your code, allowing you to easily tweak or use new platform features instantly at native code speeds. Whether you have already developed multiple applications or zero applications, this book will help you to develop your next application in a cross-platform framework quickly, saving you a massive amount of time and money. This book concisely shows you NativeScript’s built-in framework that allows you to rapidly develop a fully-working compiled cross-platform application in just a few chapters. It starts by laying the foundation of NativeScript and working through the fundamentals to create a basic shell of the application. Moving on, you’ll see how to build a full-fledged application step by step. We’ll show you how to use plugins, and how to communicate with the native OS libraries easily so that you can customize your application as if your app was created in Java or Objective C. We then deal with the issues that arise from being cross platform and compensate for the different screen sizes, screen resolutions, and device abilities. Finally, we progress to testing and deploying your app.
Table of Contents (15 chapters)
Getting Started with NativeScript
About the Author
About the Reviewer


If you are looking at this book, maybe you want to know why you should use NativeScript and what sets it apart from the crowded competition. Why shouldn't you use any of the other cross-platform tools? Let us dig in, and I'll explain why NativeScript is the answer to the best way of executing cross-platform mobile development.

Telerik's NativeScript

Telerik's NativeScript is a fairly new open source development system for creating cross-platform mobile applications almost entirely in JavaScript, with some optional CSS and XML to simplify developing the display layout. You can find the main location of each of the different projects that make up NativeScript at Even though it is new to the market, it is already fully compatible on Apple's iOS and Google's Android. In addition, Microsoft's Windows 10 Mobile is currently in development by Telerik, and others are working on Firefox Mobile. NativeScript uses the V8 engine (as used by Google Chrome and node.js) on Android and Apple's JavaScriptCore engine on iOS devices.

Other competitors

Now, there are several other competing JavaScript development systems for mobile devices. Some of these competitors have been established for a while. Other development systems may have large companies working on them. But neither of those will make any of the other tools the best choice. What makes NativeScript stand out from the crowd of other JavaScript environments is its unique design. Every other JavaScript environment requires a special bridge, or a compiled extension of some sort, which basically exposes some part of the native functionality of the host operating system to your JavaScript code. A lot of them are actually just web browsers wrapped in an application shell, so all the work you do is actually in a browser. If you decide you want Bluetooth on your iOS phone in one of the other products, you have to find someone who has made the iOS Bluetooth bridge or extension module in some other non-JavaScript language. In a lot of cases, you will even have to compile the module, and then you will still be hoping that the module has all the functionality you need.

NativeScript uniqueness

NativeScript is unique because it allows you to access the native elements of the host platform via JavaScript. In NativeScript, you can still see if someone has written a convenient JavaScript library to access the Bluetooth API. If so, since you understand JavaScript, you can easily make any changes you need. If not, then you can make your own JavaScript module to access all the host platforms of Bluetooth API. NativeScript is not a wrapper around a web view; it literally allows your JavaScript to work directly with the host platform APIs.

For example, to find out if a file exists, we can just call the native Android method in JavaScript:

var javaFile = new'/some/file/name.ext');
var exists = javaFile.exists();

Or the native iOS Objective C code in JavaScript:

var fileManager = NSFileManager.defaultManager();
var exists = fileManager.fileExistsAtPath('/some/file/name.ext');

Since NativeScript allows you access to the full operating system libraries and third-party libraries from your JavaScript code, you do not need to wait for someone else to create a wrapper or bridge to talk to any part of any iOS or Android API. You can now fully use any of the APIs as a first-class citizen, which even includes using any new APIs when they are first released.


NativeScript allows you to be a fully first-class citizen; you have FULL access to the devices' entire released API from JavaScript. So anything that you can do in Android Java or iOS Objective C, you can now do directly in JavaScript.

NativeScript is easy

Now, before you get worried about having to know both iOS and Android to make your application, NativeScript has that covered. To simplify things, NativeScript already has a wide number of components, or modules, that wrap the most common things a developer will need, which are called the NativeScript common core modules. So, instead of having to write any Android or iOS specific code like I did above to see if a file exists, you can just write the following code:

var fs = require('file-system');
var exists = fs.File.exists(path);

The NativeScript filesystem module has each of the native platforms' API wrapped up so all you have to do is write to a common interface. But when you need to do something outside of the built-in modules and components, NativeScript is the only environment that allows you to easily have full access to everything the device offers right from JavaScript.