Managing data with Angular 2: Setting and retrieving values

In my current project, I am working on developing a service that can parse data to different components based on various routes.

When I call this service within the same component, everything works as expected and I get the desired results. However, when I attempt to retrieve the set results from another component, the service returns undefined.

Below is the code snippet for my service:

import {Injectable} from '@angular/core';

@Injectable()
export class TestService {

  public _test:any;

  set test(value:any) {
    this._test = value
  }

  get test():any {
    return this._test;
  }
}

I assign a value to the service like so:

this.testService.test = 3;

To access the data stored in the service within my component, I use the following code:

console.log(this.testService.test)

While this setup functions correctly when used within the same component with matching imports, providers, and constructor, it does not work across sibling components.

If anyone has any suggestions or solutions to this issue, your help would be greatly appreciated.

If you need any additional code snippets or information, please feel free to let me know.

Answer №1

If you need to share a service among components that are not directly related as children of the same parent component, it's important to register the service at the module level rather than within an individual component. By registering a service at the module level, you ensure that it is accessible to all components within that module.

Here's an example of how this can be done:

@NgModule({
  declarations: [
    AppComponent,
    ProductListComponent,
    StarComponent
  ],
  imports: [
    BrowserModule,
    FormsModule,
    HttpModule
  ],
  providers: [ TestService ],
  bootstrap: [AppComponent]
})
export class AppModule { }

Answer №2

When attempting to communicate between two components belonging to separate modules, it is necessary to import the service into the app module (main module). By doing so, the get method will not return an error.

Answer №3

To properly initialize the testService variable, you can utilize the following code snippet within the constructor of your Component.ts file. This approach should address any instances where the var is undefined.

constructor (private testService: TestService ){
      // The testService variable is now initialized
     console.log(this.testService.test);
}

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