blink_subscribe.ts

const show$ = Observable.timer(0, 1000);
const hide$ = Observable.timer(750, 1000);

const blinker$ = Observable.merge(
  show$,
  hide$
);

blinker$.subscribe(value => console.log(value));


// Delay:    Output:
/*   0 ms */ 0
/* 750 ms */ 0
/* 250 ms */ 1
/* 750 ms */ 1
/* 250 ms */ 2
/* 750 ms */ 2
/* 250 ms */ 3
/* 750 ms */ 3
/*  ...   */