Angular中如何配置服务？

Question

I have a root service that has composition inside like:

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

@Injectable({
  providedIn: 'root',
})
export class MapService {
   
  private rmap: RMap;

  init(props: Props) {
      this.rmap = new RMap(props);
  }

  getMapLayers() {
     return this.rmap.layers;
  }

}

Problem is that new RMap(); has inside async functions. And when I use getMapLayers() from service it gives me error as undefined , because some functionality inside new RMap() are not ready. They are async.

How to solve this more properly?

As I mentioned above I get props from input:

@Input() props: Props;
constructor(private rMap: RMap) {
  this.rMap.init(this.props) {
 } 
}

But in anothe root service I get undefined on the line this.rMap.interactiveMap.getSourceId(); :

@Injectable({ providedIn: 'root' })
export class SearchyService {
    constructor(private rMap: RMap) {
        this.drawResourceId = this.rMap.interactiveMap.getSourceId();
    } 
}

Because RMap has some async.

Answer 1

You have to use async/await for this, or the promise.then in order to wait for the function to be ready.

Something like this:

async getMapLayers() {
    await this.map.getLayers()
}

And the place the you are calling the this function, will be like this:

async gettingLayers() {
  this.mapService.init();
  await this.mapService.getMapLayers()
}

You can read more about Promises here: https://developer.mozilla.org/en-US/docs/Learn/JavaScript/Asynchronous/Async_await