Important update: RxJS 5.5 brought us Lettable Operators that eliminate some of the problems noted below. If you can update to TypeScript 2.4, RxJS 5.5, Angular 5 and Angular CLI 1.5, you should definitely go with Lettable Operators.
Angular has some third-party dependencies, one of which is RxJS, a library which makes reactive programming very easy to use. The library is obtained as an npm package. In order to use functionality from the RxJS library, it has to be imported first. So before you can use an operator such as
map in the following snippet, it has to be imported:
.map(params => params.id)
.subscribe(id => console.log(id));
Whereas IDEs such as WebStorm (prior to 2017.2) or Visual Studio Code do a good job for auto-importing symbols, they don’t suggest anything at all for RxJS symbols. Both IDEs simply print the following error message from TypeScript:
Property ‘map’ does not exist on type ‘Observable’.
Continue reading Angular & TypeScript: How to Import RxJS Correctly?
On May 4, Angular 4.1.1 was released. This release fulfils a promise already made for Angular 4.1: Adding support for TypeScript’s
strictNullChecks compiler option added in TypeScript 2.0.
Strict Null Checking = Safer Code
This transpiler flag enables us to write safer code. TypeScript with strict null checking enabled feels even more comfortable for developers with a static-typed language background. Without strict null checking, assigning
undefined for instance to a variable of type
number is perfectly possible:
Continue reading Angular & TypeScript: Writing Safer Code with strictNullChecks
On Mac OS X, everything looked nice. But on Windows, the column headers were oddly shifted and did not match the content columns. While investigating the bug, we found out that the columns were shifted by exactly 17 pixels to the left. But why 17 pixels? And not 5, 10, 15 or anything power of 2?
Continue reading The Mysterious 17 Pixels Shift
Recently we brought a Cordova-based web app which already runs successfully on iOS and Android to Windows Phone 8.1. One of the issues you will definitely come across when porting your app to this platform is the handling of the back button, an essential part of Windows Phone’s user experience.
By default, pressing the back button on Windows Phone closes your Cordova-based app, regardless of the current state. Instead, the back button should bring you back to the previous view; except on the main page, where pressing it must suspend the current app (according to the Windows Store Policies, 10.4.4):
Where applicable, pressing the back button should take the user to a previous page/dialog. If the user presses the back button on the first page of the app, then the app terminates (unless it is allowed to run in the background).
Not respecting those policies may not only lead to a rejection of your app, but also to bad ratings in the Store.
Continue reading Looking Back: AngularJS, Cordova and the Windows Phone Back Button
Detail of Michelangelo’s Creation of Adam
Your customers love mobile devices and apps. And they love the way of interacting with them, using touch.
Touch is a very natural input method and multi-touch allows intuitive gestures such as pinch-to-zoom. As mobile or web developers, we also love apps and touch interaction. But, face it, we are also quite lazy. We want to run code written once to execute on several browsers and platforms resulting in one and the same behavior. Unfortunately, there are two competing methods that allow interacting with websites using touch input:
Continue reading Enabling Cross-Platform Touch Interactions: Pointer vs. Touch Events