Ways to pass data to a different module component by utilizing BehaviourSubject

Question

Ways to pass data to a different module component by utilizing BehaviourSubject

In multiple projects, I have used a particular approach to pass data from one component to another. However, in my current project, I am facing an issue with passing data from a parent component (in AppModule) to a sidebar component (in CoreModule) upon dropdown change. The problem is that the subscribe method in the sidebar component, which acts as the child component in this scenario, does not trigger after the initial load. Could this be due to the components being in different modules, or is there another underlying issue?

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Update:

This is how the modules are structured:

parent.module:

imports: [
   SharedModule
],
providers: []

child.module:

imports: [
   SharedModule
],
providers: []

shared.module:

providers: [
    DataService
]

Even with the above setup, the issue persists. Moving DataService from shared.module to app.module resolves it, but I believe it should work fine within shared.module. Why is that?

javascript angular typescript rxjs observable

Answer 1

Answer №1

It seems like the issue may be related to how providers are instantiated in each module. Have you considered only adding one provider to the top parent module to see if that resolves the issue?

There is a distinction between using components and services from other modules. When importing modules, it's important to note that using directives, pipes, and components will create new instances of those elements. Importing a module with services will result in a new instance of the service, which may not be desired if you want to reuse an existing service. Utilize module imports to manage service instantiation effectively.

Typically, shared services are accessed through Angular dependency injection rather than through module imports, as this can lead to unexpected behavior (such as creating multiple instances of a service when not intended).

To learn more about sharing services, refer to the Providers section on the Angular documentation.

In essence, when you import a new module, a new instance of the provider is created for each import, resulting in different injections. If you require consistent data across both modules, consider handling the provider in the AppModule.

Answer 2

It seems like the issue may be related to how providers are instantiated in each module. Have you considered only adding one provider to the top parent module to see if that resolves the issue?

There is a distinction between using components and services from other modules. When importing modules, it's important to note that using directives, pipes, and components will create new instances of those elements. Importing a module with services will result in a new instance of the service, which may not be desired if you want to reuse an existing service. Utilize module imports to manage service instantiation effectively.

Typically, shared services are accessed through Angular dependency injection rather than through module imports, as this can lead to unexpected behavior (such as creating multiple instances of a service when not intended).

To learn more about sharing services, refer to the Providers section on the Angular documentation.

In essence, when you import a new module, a new instance of the provider is created for each import, resulting in different injections. If you require consistent data across both modules, consider handling the provider in the AppModule.

Answer 3

Answer №2

It is recommended to register all your services with the root Injector. Instead of providing services to individual modules or components, you can set provideIn: 'root':

@Injectable({provideIn: 'root'}) 
export class DataService { ... }

(and remember to remove it from the providers arrays).

The issue you might be facing could be due to lazy loading of modules, resulting in each module having its own injector and causing multiple instances of the service to be created.

To resolve this, consider using the suggested approach or learn more about utilizing forRoot() and forChild() if you prefer to keep your service within a module's providers array.

Answer 4

It is recommended to register all your services with the root Injector. Instead of providing services to individual modules or components, you can set provideIn: 'root':

@Injectable({provideIn: 'root'}) 
export class DataService { ... }

(and remember to remove it from the providers arrays).

The issue you might be facing could be due to lazy loading of modules, resulting in each module having its own injector and causing multiple instances of the service to be created.

To resolve this, consider using the suggested approach or learn more about utilizing forRoot() and forChild() if you prefer to keep your service within a module's providers array.

Ways to pass data to a different module component by utilizing BehaviourSubject

Answer №1

Answer №2

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