// First,create a separate observable for each event:
const scrollEvents$   = Observable.fromEvent($element,'scroll');
const wheelEvents$    = Observable.fromEvent($element,'wheel');
const touchMoveEvents$= Observable.fromEvent($element,'touchmove');
const touchEndEvents$ = Observable.fromEvent($element,'touchend');

// Then,merge all observables into one single stream:
const allEvents$= Observable.merge(
    scrollEvents$,wheelEvents$,touchMoveEvents$,touchEndEvents$
);

如果这看起来有点臃肿,我们可能会通过为事件创建一个数组来清理一下,然后将该数组映射到Observable对象.如果您不需要在某些时候单独引用其关联的可观察事件,则此方法效果最佳：

const events = [
    'scroll','wheel','touchmove','touchend',];

const eventStreams = events.map((ev) => Observable.fromEvent($element,ev));
const allEvents$= Observable.merge(...eventStreams);

您现在可以使用一个订阅来处理所有事件：

const subscription = allEvents$.subscribe((event) => {
    // do something with event...
    // event may be of any type present in the events array.
});