如何在RxJS中超时事件？

Question

我试图检测mousedown事件是否在a之前保持了一段时间mouseup.

我在使用fromEvent()这样做的Observable上使用timeout(),但是超时返回两个Observable.

下面,订阅流返回事件,如果mousedown在1秒内触发,但它也返回1.

var mousedown = Rx.Observable.fromEvent(target, 'mousedown');
var stream = mousedown.timeout(1000, Rx.Observable.return(1));

var sub = stream.subscribe(
    function (x) { 
        console.log('Next: '+x);
    },
    function (err) {
        console.log('Err: '+err);
    },
    function () {
        console.log('Complete');
    }
);

但是,这可以按预期工作:

var source = Rx.Observable.return(42)
    .delay(200)
    .timeout(1000, Rx.Observable.return(1));

我希望这段代码能够正常工作:

var mousedown = Rx.Observable.fromEvent(target, 'mousedown');
var mouseup = Rx.Observable.fromEvent(target, 'mouseup');

var clickhold = mousedown
.flatMap(function (){
    return mouseup.timeout(1000, Rx.Observable.return('hold'));
})
.filter(function (x) {
    return x === 'hold';
});

clickhold.subscribe(
    function (x) { 
        console.log('Next: '+x);
    },
    function (err) {
        console.log('Err: '+err);
    },
    function () {
        console.log('Complete');
    }
);

Answer 1

而不是使用timeout,我使用delay和takeUntil:

var target,
    mousedown,
    mouseup;

target = document.querySelector('input');

mousedown = Rx.Observable.fromEvent(target, 'mousedown');
mouseup = Rx.Observable.fromEvent(target, 'mouseup');

var clickhold = mousedown
    .flatMap(function(){
        // Triggered instantly after mousedown event.
        return Rx.Observable
            .return('hold')
            .delay(1000)
            // Discards the return value if by the time .delay() is complete
            // mouseup event has been already completed.
            .takeUntil(mouseup);
    });

clickhold.subscribe(
        function (x) { 
            console.log('Next: ' + x);
        },
        function (err) {
            console.log('Err: ' + err);
        },
        function () {
           console.log('Complete');
        }
    );

<script src='https://rawgit.com/Reactive-Extensions/RxJS/v.2.5.3/dist/rx.all.js'></script>

<input type='button' value='Button' />