The subscribe magic disappeared

[kyo4311]

$(document)
    .readyAsObservable()
    .flatMap(function(obj) {
        return $.ajaxAsObservable({
            url: 'cityList',
            dataType: 'jsonp'
        });
    })
    .flatMapLatest(function(res) {
        return res.list; // is Arrary
    })
    .reduce(function(acc, x, idx, source) {
        alert(acc); //has data
        return acc + '<div></div>';
    }, '')
    .subscribe(function(x) {
            alert(x); //Does not perform
        }, function(err) {
            alert(err); //Does not perform
        },
        function() {
            alert('Completed'); //Does not perform
        });