Angular 2: Convert Observable to Promise

Question

Q) How do I convert the following observable to a promise so I can call it with .then(...)?

My method I want to convert to a promise:

Answer 1

toPromise is deprecated in RxJS 7.

Use:

1. lastValueFrom

Used when we are interested in the stream of values. Works like the former toPromise

Example

public async getAssetTypes() {
  const assetTypes$ = this._APIService.getAssetTypes()
  this.assetTypes = await lastValueFrom(assetTypes$);
}

2. firstValueFrom

Used when we are not interested in the stream of values but just the first value and then unsubscribe from the stream

public async getAssetTypes() {
  const assetTypes$ = this._APIService.getAssetTypes()
  this.assetTypes = await firstValueFrom(assetTypes$); // get first value and unsubscribe
}