Can components in Angular be dependency injected? I am interested in a solution similar to injecting services, like the example below:
my.module.ts:
providers: [
{
provide: MyService,
useClass: CustomService
}
]
I attempted using *ngIf="condition" in a wrapper component, but encountered issues with service injection for unused components.
Having a parent-child relationship between components allows for easy dependency injection between them. If you have a setup like the one below:
@Component( {
selector:"app-parent",
template:" <app-child> </app-child>"
} )
export class ParentComp { ...}
You can inject the parent component inside the child component using dependency injection.
@Component({
selector:"app-child",
template:"I am child"
})
export class ChildComponent{
constructor(private parentComp:ParentComponent){
}
}
The Angular DI system will recognize that you need access to the parent component of the child and handle the injection for you.
If you need to inject a component that does not have a parent-child relationship, such as wanting to inject a sidenav component into a table component outside of the sidenav's structure, it is technically possible but not recommended. In such cases, creating a shared service to manage state between these components is a better approach.
Absolutely, you have the flexibility to assign any value (whether it be a constant, function, or class) to a specific injection token. A great example is incorporating components providing functionality in tandem with the implementation of ControlValueAccessor
@Component({
providers: [
{
provide: NG_VALUE_ACCESSOR,
useExisting: forwardRef(() => CustomInputComponent),
multi: true
}
]
})
export class CustomInputComponent {...}
You also have the ability to create your own unique injection token and furnish it with any resources you desire for both tokens and components.
/* Within tokens.ts */
const MY_TOKEN_NAME = new InjectionToken<MyAmazingComponent>('MY_TOKEN_NAME')
/* In module */
providers: [
{ provide: MY_TOKEN_NAME, useClass: MyAmazingComponent }
]
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