Javascript Node.js"；fs.writeFile（）；Promise.all内部的回调在Promise.all解析后执行

在使用Promise.all编写了一堆文件之后，我正在尝试记录一些东西。但不知何故，数组中的最后一个文件总是在Promise.all解决后调用

请参阅下面的代码和输出

Promise.all(videos.map(async (video) => {
            const dest = `${destinationFolder}/${video.name}`;
            const response = await fetch(video.url);
            const buffer = await response.buffer();
            await fs.writeFile(dest, buffer, () => {
                console.log(`✔ Downloaded video: ${video.name} to ${dest}`);
            });
        }
    )).then(() => {
        console.log(`✨ Downloaded all videos to ${destinationFolder}`);
    });

预期产出：

✔ Downloaded video: video1.mp4 to ./dest/video1.mp4
✔ Downloaded video: video2.mp4 to ./dest/video2.mp4
✨ Downloaded all videos to ./dest

实际产量：

✔ Downloaded video: video1.mp4 to ./dest/video1.mp4
✨ Downloaded all videos to ./dest
✔ Downloaded video: video2.mp4 to ./dest/video2.mp4

---

fs.writeFile

使用回调返回结果，但不返回承诺。 您可以使用

newpromise

将此回调调用转换为异步调用

const writeFilePromise = new Promise((resolve, reject) => {
  fs.writeFile(dest, buffer, (err) => {
                if (err) {
                  reject(err)
                }
                console.log(`✔ Downloaded video: ${video.name} to ${dest}`);
                resolve()
            });
});
await writeFilePromise;

---

要使用

await

，您需要返回承诺的函数版本，此版本位于

promises

命名空间中：

Promise.all(videos.map(async (video) => {
    const response = await fetch(video.url);
    const destination = `${folder}/${video.name}`;
    await fs.promises.writeFile(destination, await response.buffer());

    console.log(`✔ Downloaded video: ${video.name} to ${destination}`);
)).then(() => {
    console.log(`✨ Downloaded all videos to ${folder}`);
});

---

writeFile

接受回调，但不返回承诺。您不能等待它。使用

fs.promise

谢谢，这个解决方案很有效，但我更喜欢上面提到的@z1ne2wo现有的解决方案。