rxjs execute tap only at the first time

Question

I want to execute tap() only when i get the first emitted value

Something like:

Observable
  .pipe(
     tap(() => { /* execute only when I get th         


        

Answer 1

(Updating my earlier incorrect answer)

Based on cartant's comment and link provided, he has already done the work to create an operator that does this, it is in the 'rxjs-etc' package. A solution based on his operator is to install 'rxjs-etc', then:

import { initial } from 'rxjs-etc/operators';

observable$.pipe(
    initial(src$ => src$.pipe(tap(() => {/* execute only on first value */})))
).
subscribe(() => {
    // ..... 
})

Working StackBlitz example.