var foo = Rx.Observable.interval(500).take(5);

/*

--0--1--2--3--4|

 delay(1000)

-----0--1--2--3--4|

*/

// delay(1000)

var result = foo.delay(1000);

result.subscribe(

  function (x) { console.log('next ' + x); },

  function (err) { console.log('error ' + err); },

  function () { console.log('done'); },

);

var foo = Rx.Observable.interval(500).take(5);

/*

--0--1--2--3--4|

 delay(date)

-----0--1--2--3--4|

*/

var date = new Date(new Date().getTime() + 1000);

var result = foo.delay(date);

result.subscribe(

  function (x) { console.log('next ' + x); },

  function (err) { console.log('error ' + err); },

  function () { console.log('done'); },

);

var foo = Rx.Observable.interval(500).take(5);

/*

--0--1--2--3--4|

 delayWhen(x => --------0--------...)

--------0--------1--------2--------3--------4|

*/

// delay(1000)

var result = foo.delayWhen(x =>

  Rx.Observable.interval(x * 1000) // For each foo, it will delay 1000 * x, so '2' --> 2000, '3' ---> 3000

);

result.subscribe(

  function (x) { console.log('next ' + x); },

  function (err) { console.log('error ' + err); },

  function () { console.log('done'); },

);