Rx.Observable.repeat (indefinitely) with zip causes the browser to stop responding - rxjs

Question

The following code causes the browser to stop responding, using a value like '100' for example for the repeat solves the problem, but in my case I don't have specific value for it.
Would you please suggest a solution:
var observer = Rx.Observer.create(function (x)
{
console.log(x);
},
function (err)
{
console.log('Error: ' + err);
},
function ()
{
console.log('Completed');
});
var repeat = Rx.Observable.repeat(10, null); //repeat indefinitely
var interval = Rx.Observable.interval(1000);
var zip = Rx.Observable.zip(repeat,
interval,
function(rep, inter)
{
return rep + inter;
});
zip.subscribe(observer);

Answer 1

The browser freezes because .repeat simply yields 10 indefinitely.
Since Rx is push-based, we have no way of knowing when zip needs another item. Instead, we just push new values to zip as they become available. The static (class-method?) repeat says "hey, I have new items RIGHT NOW ALWAYS HERE THEY ARE" and never relinquishes control-flow back to zip. This means zip never actually ends up subscribing to the interval observable, so zip just starts buffering indefinitely.
If you're coming from a functional background, then it would seem like an "infinite" list of "10"s would zip nicely with a finite list of anything. Which is absolutely true, assuming your infinite list is lazy. In this case, our "list" has a mind of it's own, and definitely isn't lazy.
I'd be happy to suggest a solution, but it seems that the example is contrived. What exactly are you attempting to do?

Answer 2

I was dealing with the same problem. Looks like delay can do the trick.
Here's the slightly modified version of your code:
var observer = Rx.Observer.create(function (x)
{
console.log(x);
},
function (err)
{
console.log('Error: ' + err);
},
function ()
{
console.log('Completed');
});
var repeat = Rx.Observable.of(10).delay(0).repeat(-1); //repeat indefinitely
var interval = Rx.Observable.interval(1000);
var zip = Rx.Observable.zip(repeat,
interval,
function(rep, inter)
{
return rep + inter;
});
zip.subscribe(observer);