Is there a way to verify if another component has provided an @Input() in my component? I'm unsure when the best time is to check for this. Should I do it during 'ngOnInit', 'ngAfterViewInit' or perhaps something else?
Is there a way to verify if another component has provided an @Input() in my component? I'm unsure when the best time is to check for this. Should I do it during 'ngOnInit', 'ngAfterViewInit' or perhaps something else?
To determine if a change has occurred, you can use the ngOnChanges method in the following way:
export class MyComponent implements OnChanges {
@Input() input;
ngOnChanges(changes: SimpleChanges): void {
if (changes.hasOwnProperty('input')) {
if (changes['input'].isfirstChange()) { // This indicates initialization by Angular
performInitialization();
} else { // Indicates an actual change based on your conditions
performAdditionalActions();
}
}
}
}
One option is to verify data in either ngOnInit or ngAfterViewInit, although there is no guarantee that the expected data will be available (such as if it comes from an HTTP request or calculations).
It might be a good idea to utilize the OnChanges interface and make use of ngOnChanges since it reacts to any changes in input data.
Referencing the documentation,
A callback method that triggers immediately after the default change detector checks bound properties for changes, prior to checking the view and content children.
How do you intend to utilize the @Input() feature exactly? If your goal is to pass input across different components (child, sibling, and parent), I strongly recommend using services instead. Services are easier to manage and verify compared to using inputs (in my personal experience).
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