Demo:  skipWhile

skipWhile skips the incoming values until the given condition fail for the first time.

skipWhile(skipCondition)

//Emit the items every 1 sec
let input = of(2,5,4,6,5,3,2,8)
        .pipe(concatMap(v=>of(v).pipe(delay(1000))));

//skip items until the condition fails for the first time
let process = skipWhile(v => (v < 6));

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