javascript - 我如何将这段代码放入可重用的函数中？

Question

我在 stackoverflow 上发现这段代码会慢慢淡出音轨。它运作良好。它的结构方式我发现如果不复制和粘贴就很难重复使用，因为该函数在自身内部调用自身。这是代码:

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

除了 gameController.myAudio.preGameTrack 之外，每个语句都将保留。

将其存储在一个变量中并传入。如果您在该上下文中交谈，应该可以重复使用。

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;
})