我如何將這段代碼放入可重用的函數中？

Question

我在stackoverflow上發現了這段代碼，它逐漸淡出了音軌。 它運作良好。 它的結構使我很難在沒有復制和粘貼的情況下重復使用，因為該函數在自身內部進行調用。 這是代碼：

function fadeVolume(volume, callback) {
    //change the volume by factor each time
    //will check if setTimeout is used to loop as well as wait, as it seems so here
    var factor = 0.02,
        speed = 50;
    if (volume > factor) {
        setTimeout(function () {
            fadeVolume((gameController.myAudio.preGameTrack.volume -= factor), callback);
        }, speed);
    } else {
        (typeof (callback) !== 'function') || callback();
    }
};
fadeVolume(gameController.myAudio.preGameTrack.volume, function () {
    preGameContent.ready = true;
    //stop the music altogether
    gameController.myAudio.preGameTrack.pause();
    gameController.myAudio.preGameTrack.currentTime = 0;
})

Answer 1

除gameController.myAudio.preGameTrack之外的所有語句都將保留。

將其存儲在變量中並傳遞。如果在這種情況下進行交談，應可重用。

function fadeVolume(track, factor, speed, callback) {
    //change the volume by factor each time
    //will check if setTimeout is used to loop as well as wait, as it seems so here

    if (track.volume > factor) {
        setTimeout(function () {
            fadeVolume((track.volume -= factor), callback);
        }, speed);
    } else {
        (typeof (callback) !== 'function') || callback();
    }
};

var track = gameController.myAudio.preGameTrack,
    factor = 0.2,
    speed = 50;
fadeVolume(track, factor, speed, function () {
    preGameContent.ready = true;
    //stop the music altogether
    track.pause();
    track.currentTime = 0;
})