Demo:  min

The min operator finds the minimum number out of all the input numbers from the source and emits it as the source completes.

min();

//Each input is delayed by 1 sec
let input = of(50,15,20,12,30,90,30,60)
        .pipe(concatMap(v => of(v).pipe(delay(1000))))

//Find the min of all the input
let process = min();

let output=input.pipe(process).subscribe(v=>console.log(v))