feat: introduce dioc into hoppscotch-common

packages/dioc/lib/service.ts

@@ -0,0 +1,65 @@
+import { Observable, Subject } from 'rxjs'
+import { Container, currentContainer } from './container'
+
+/**
+ * A Dioc service that can bound to a container and can bind dependency services.
+ *
+ * NOTE: Services cannot have a constructor that takes arguments.
+ *
+ * @template EventDef The type of events that can be emitted by the service. These will be accessible by event streams
+ */
+export abstract class Service<EventDef = {}> {
+
+  /**
+   * The internal event stream of the service
+   */
+  private event$ = new Subject<EventDef>()
+
+  /** The container the service is bound to */
+  #container: Container
+
+  constructor() {
+    if (!currentContainer) {
+      throw new Error(
+        `Tried to initialize service with no container (ID: ${ (this.constructor as any).ID })`
+      )
+    }
+
+    this.#container = currentContainer
+  }
+
+  /**
+   * Binds a dependency service into this service.
+   * @param service The class reference of the service to bind
+   */
+  protected bind<T extends typeof Service<any> & { ID: string }>(service: T): InstanceType<T> {
+    if (!currentContainer) {
+      throw new Error('No currentContainer defined.')
+    }
+
+    return currentContainer.bind(service, this.constructor as typeof Service<any> & { ID: string })
+  }
+
+  /**
+   * Returns the container the service is bound to
+   */
+  protected getContainer(): Container {
+    return this.#container
+  }
+
+  /**
+   * Emits an event on the service's event stream
+   * @param event The event to emit
+   */
+  protected emit(event: EventDef) {
+    this.event$.next(event)
+  }
+
+  /**
+   * Returns the event stream of the service
+   */
+  public getEventStream(): Observable<EventDef> {
+
+    return this.event$.asObservable()
+  }
+}