rxjs - 如何使 RxJS 中的事件超时？

Question

我正在尝试检测 mousedown 事件是否在 mouseup 之前持续了一段时间。

我在使用 fromEvent() 创建的 Observable 上使用 timeout() 来执行此操作，但超时会返回两个 Observable。

下面，如果 mousedown 在 1 秒内被触发，订阅流返回事件，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 , 我用过 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');
        }
    );

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