RxJS filter a list based on a list - reactive-programming

Question

If I have a list where the number of arguments vary (or can be updated):
SomeDynamicListofPreferences = [
'Chocolate',
'Strawberry',
'Vanilla'
];
What (if any) would be a good RxJS way to dynamically filter a list of matches based on a main source stream?
StockedFlavors = [
'Almond Mocha',
'Banana',
'Butter Pecan',
'Chocolate',
'Coconut Cream',
...
'Strawberry',
'Vanilla'
];
Ex: Based on what I've learned so far one possibility is:
let dynamicPreferences = Rx.Observable.fromArray(SomeDynamicListofPreferences);
let StockedStream = Rx.Observable.fromArray(StockedFlavors);
let PrefMatches = StockedStream.filter((flavor) =>
dynamicPreferences.includes(flavor) ).
subscribe((x) => { if(x){ /*...do stuff */ }});
The "includes" operator feels like a loop within a loop. I could see another scenario of iterating the raw SomeDynamicListofPreferences to generate individual filterStreams.
Any help regarding technique and/or scale is greatly appreciated.

Answer 1

this works for me... ymmv
function deferSource(source) {
// wrapping in the defer gives us a unique snowflake observable
return Rx.Observable.defer(function() {
// your returned observable may vary as well...
return Rx.Observable.fromArray(source);
})
}
// your observable sources may vary
var preferenceList = [
'Chocolate',
'Strawberry',
'Vanilla'
];
var flavorList = [
'Almond Mocha',
'Banana',
'Butter Pecan',
'Chocolate',
'Coconut Cream',
'Strawberry',
'Vanilla Bean'
];
var prefrence$ = deferSource(preferenceList)
var flavor$ = deferSource(flavorList);
function curryQuery(static$source) {
return function querySourceForResults(dynamic_element) {
return static$source
.filter(function(static_element){
return static_element.includes(dynamic_element)
})
}
}
prefrence$.flatMap(curryQuery(flavor$)).subscribe(logger('result'))