How do I create a service?

Generate a service

npm run generate service services/example # target directory: src/app/services/example

Example service

// example.service.ts
import { Service } from '../../../core/index.js';

export class ExampleService extends Service<ExampleService> {
  constructor() {
    super();
  }

  public doThing(): void {
    // ...
  }
}

export const exampleService = ExampleService.getInstance();

Service<T> is an abstract singleton base. Calling new ExampleService() directly throws — getInstance() is the only valid way to construct one:

public static getInstance<C extends new (...args: any) => Service<any>>(this: C, ...args: ConstructorParameters<C> | []): InstanceType<C>

The Service class is exported only for testing purposes.

The arguments are type-checked against the service's constructor (a service without one accepts none), and the result is typed as that service. The first call constructs and caches the instance; every later call returns the same one. Calling getInstance(...) with arguments after the instance already exists throws — pass constructor args only on the very first call (typically the one in the module that defines the exported const), and call getInstance() with no arguments everywhere else.

Every service method is auto-bound to the instance at construction, so its methods can be passed around as bare callbacks without losing this — see How do I use a service?.