That’s the kind of thing I do once every 6 months, and I always forget what’s the damn file to modify to persist alias on Debian.
Modify ~/.bashrc, and add your alias, for example :
alias ll='ls -l'A common Angular beginner error is forgetting to unsubscribe from observables. This leak may not be noticeable at first, but will eventually lead to a sluggish application, or other unexpected behaviours.
One can manually keep track of all subscriptions, in order to properly unsubscribe in ngOnDestroy. However, this is tedious, and error prone.
Depending on your subscription context, there are two solutions that you may like.
For a subscription which is a one shot, you need to retrieve your data, and then fortget it, the RxJS first operator combined if straightforward.
myObservable.pipe(first()).subscribe(...);If you’re expecting several events, and need to unsubscribe only when the component gets destroyed, then @ngneat/until-destroy, is “a neat way to unsubscribe from observables when the component destroyed“
The @UntilDestroy({ arrayName: ‘subscriptions’ }) is a nice way to both explicit the requirement for observables to be unsubsribeds, while minimizing boilerplate code.
When working with JPA / Hibernate, you may want to prevent updates of a given column. This is typically the case with your primary key. This is possible using the “updatable” attribute of the @Column annotation. Ex :
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "id", updatable = false, nullable = false)
private Long id;You have an angular component, and would like to have a value with a two way binding similar to ngModel. The easiest way is to :
For example :
@Component({
selector: 'app-select-nature-document',
template: './select-nature-document.component.html',
styleUrls: ['./select-nature-document.component.css']
})
export class SelectNatureDocumentComponent implements OnInit {
@Input()
natureDocument: NatureDocument;
@Output()
natureDocumentChange: EventEmitter<NatureDocument> = new EventEmitter<NatureDocument>();
...
You can then notify the value change using the output event emitter :
onNatureDocumentSelected() {
this.natureDocumentChange.emit(this.natureDocument);
}And the component can be used like this :
<app-select-nature-document [(natureDocument)]="editedDocument.nature"></app-select-nature-document>Thanks to https://stackoverflow.com/questions/42006770/angular2-component-input-two-way-binding.