Skip to main content

Posts

Showing posts from January, 2018

Angular for Java EE developers

Being a Java EE developer for a long time and trying to find a development platform in these times where more and more business logic is placed in the frontend code, Angular (NOT AngularJS) became a natural choice. Being used to Java Server Faces with backend beans, coding with Angular is quite similar. You still have a HTML template and a separate class (Angular components ) with the template logic, but now this is all part of the frontend code. Also quite a bit of the code you would earlier place in EJB session beans can be put in Angular services , which can be injected into components using dependency injection . All together with TypeScript which gives you static types, decorations (annotations), classes and interfaces that any Java developer will miss when coding with Javascript. Now that the client / frontend does more and more of the traditional backend work, and the backend is more about providing data and access control than application business logic - Angular is a f

Angular components not reloading on route change

Spent a long time wondering why route changes caused strange effects on my component, and found out that it was because my component wasn't reloading at all. I had this assumption that when a route parameter changed (e.g. /projects/1 changed to /projects/2 ) the component for the route would be reloaded. But this is not the default behaviour of the Angular router. The default behaviour of the Angular router is to reuse the route if the configuration is the same (and not reload the component). But we can override this by providing a RouteReuseStrategy to our @NgModule: providers: [ { provide: RouteReuseStrategy, useClass: AARouteReuseStrategy } ] The full custom implementation of the RouteReuseStrategy will then be like this (and it's the shouldReuseRoute method that changes the behaviour so that the component is reloaded on route parameter change): export class AARouteReuseStrategy extends RouteReuseStrategy { shouldDetach(route: ActivatedRou

Multiple router outlets in Angular

Multiple router outlets in Angular makes it possible to have different sections in the view where the components are determined by the URL, and each outlet can have their own navigation. Sometimes though - let's say you use named router outlets for the toolbar and the left side menu, you want the main URL to control the components to be showed for all outlets, not just the main outlet. In this case the router outlet configurations should be children on the main path as shown in the config snippet below. This way the URL /projects/2018/myorganization will show a left side menu and a toolbar in addition to the main content component, while /projects/2018 will only show the toolbar. If you want the toolbar only to show at the projects root path, but not children then add pathMatch: 'full' . RouterModule.forChild([ { path: 'projects', children: [ { path: '',