cachedObservable

gistfile1.txt

//This doesnt work (Fails on second try)

var cachedObservable;                
var observableFms = Rx.Observable.If(function() {
    return cachedObservable !== undefined;
}, 
cachedObservable, 
Rx.Observable.Defer(function() {
    cachedObservable = service.getObservableFmsAuswertungForTour(data.ID);
    return cachedObservable;
}));

//This does work

var cachedObservable;                
var observableFms = Rx.Observable.If(function() {
    return cachedObservable !== undefined;
}, 
Rx.Observable.Defer(function(){
    return cachedObservable;
}, 
Rx.Observable.Defer(function() {
    cachedObservable = service.getObservableFmsAuswertungForTour(data.ID);
    return cachedObservable;
}));

What's wrong with the first one? Even I can see in the debugger that the cachedObservable was set correctly from the first call, the second call fails with "undefined has no method Subscribe". The second approach does work however.