Short polling until predicate is met with RXJS

rx-shortpoll.js

function getWikipediaSearchResults(term) {
    return Rx.Observable.create(function forEach(observer) {
        var cancelled = false;
        var url = 'http://en.wikipedia.org/w/api.php?action=opensearch&format=json&search='
        + encodeURIComponent(term) + '&callback=?';
        $.getJSON(url, function(data) {
          if (!cancelled) {
            observer.onNext(data[1]);
            observer.onCompleted();
          }
        });
        
        return function dispose() {
          cancelled = true;
        };
      });
}



// Create an observable that emits a new value every 2 seconds
// substitute interval for  Rx.Observable.timer(0, 2000) if you need immediate start
Rx.Observable.interval(2000)
    // cancel any pending requests
    .flatMapLatest(() => getWikipediaSearchResults('Peter'))
    // not necessary but if you need to do something with the response incase its wrapped
    .map(response => response)
    // give me the first observable that meets our predicate, which then disposes the stream
    .first((data) => {
        return data.filter(valuesInArray => valuesInArray.indexOf('LIKES') > -1)
    })
    .subscribe(data => console.log('onNext', data));