javascript - 在外部范围事件上触发 Promise.fulfill

Question

我正在使用名为 IonSound.js 的声音播放器，可以在此处找到它。 http://ionden.com/a/plugins/ion.sound/en.html

根据文档，我可以像这样监听 sound.ending 事件:

ion.sound({
    sounds: [
        {name: "door_bump"},
        {name: "water_droplet_2"},
        {name: "water_droplet_3"}
    ],
    ended_callback: function (sound) {
        // sound ended
        game.sound.soundEnded(sound);
    }
});

我在此之上制作了一个非常基本的包装器。

class Sound
{
    constructor(ion) {
        this.ion = ion;
        this.promises = {};
    }

    play(sound) {
        if (game.settings.muted === false) {
            this.ion.sound.play(sound);
        }

        this.promises[sound] = new Promise((accept, reject) => {

        });

        return this.promises[sound];
    }

    soundEnded(sound) {
        if (this.events.hasOwnProperty(sound.name) === true) {
            Promise.resolve(this.promises[sound.name])
        }
    }
}

现在，当我执行以下代码时:

game.sound.play("level-up");

ending_callback 触发器。然后它调用 sound.soundEnded。

问题是，事情变得一团糟。我想做的是 promise 我的 Sound 类，这样我就可以像这样使用它:

game.sound.play("level-up").then(() => {
    console.log("Sound is over.");
});

为了做到这一点，这段代码必须fulfill()我在this.promises哈希上保留的 promise 。

Promise.resolve(this.promises[sound.name]);

但它没有任何方法来触发执行，如下所示:

this.promises[sound.name].fulfill();

有什么想法吗？

Answer 1

不要在 this.promises 中保留一组 Promise，而是在 this.promiseFulfil 中保留一组 Promise 接受/拒绝回调。这样你就可以实现 promise 。

以下是您的类的外观:

class Sound
{
    constructor(ion) {
        this.ion = ion;
        this.promiseFulfil = {};
    }

    play(sound) {
        if (game.settings.muted === false) {
            this.ion.sound.play(sound);
        }

        // Just return the promise without storing it.    
        return new Promise((accept, reject) => {
            // keep track of which function to call to fulfil promise:
            this.promiseFulfil[sound] = { accept, reject };
        });
    }

    soundEnded(sound) {
        if (this.promiseFulfil[sound]) {
            // call the appropriate promise-callback:
            this.promiseFulfil[sound].accept();
            // optionally clear this entry:
            this.promiseFulfil[sound] = undefined;
        }
    }
}