TypeError while Implement startWith() operator in rxjs

Question

I am quite a beginner at angular and I am just trying to create an Observable and run it automatically just the first time when a particular condition is not met.

but typescript throws some errors while I use startWith() and I don't understand what to do now?

this.obsearable$ = this.id ? from(this.pt.get(this.id)) : from([]).pipe(startWith())

Error: Argument of type 'Observable' is not assignable to parameter of type 'OperatorFunction<any, unknown>'.

Type 'Observable' provides no match for the signature '(source: Observable): Observable'.ts(2345)

Answer 1

startWith仅适用于某些值（ https://www.learnrxjs.io/learn-rxjs/operators/combination/startwith ）

Answer 2

The startWith() operator is intended for observables that may not emit an initial value. In the case of your example, from() immediately emits the value contained inside its parameter, so there is no need to use startWith() .