Javascript 以“For循环”（异步）方式上载到Google云存储

我是Javascript新手。我正在尝试创建一个循环，将图像上传到谷歌云存储。使用此代码，可以正确上载图像。问题是上传后路径URL没有保存在数据库中

我尝试使用async并等待。然而，我不明白它是如何工作的。我希望for循环和里面的所有内容都在保存帖子之前完成

提前谢谢大家,

for (const [i, file] of files.entries()) {
  newFileName = "img_" + Date.now() + "_" + file.originalname;
  imagePath = getPublicUrl(newFileName);

  myfile = bucket.file(newFileName);


  stream = myfile.createWriteStream({
    metadata: {contentType: file.mimetype},
    resumable: false
  });


 sharp(file.buffer)
 .resize({ width: 1080 })
 .pipe(stream)
 .on('finish', () => {
   post.images.push(imagePath);
 })
}
post.save();

---

您希望为每个请求创建一个挂起承诺数组，然后可以将它们包装在Promise方法Promise.all[]中

例如：

// we'll push all the promises into this array:
const pendingPromises = []

for (const {i, file} of files.entries()) {
  // just wrap it in a promise 
  // and push into the promise array:
  pendingPromises.push(new Promise((resolve, reject) => {
    // do everything the same as before for each iteration
    newFileName = "img_" + Date.now() + "_" + file.originalname;
    imagePath = getPublicUrl(newFileName);

    myfile = bucket.file(newFileName);


    stream = myfile.createWriteStream({
      metadata: {contentType: file.mimetype},
      resumable: false
    });


   sharp(file.buffer)
   .resize({ width: 1080 })
   .pipe(stream)
   .on('finish', () => {
     post.images.push(imagePath);
     resolve(imagePath)
   })
  }))

}

// wait for all the async code to complete execution and resolve before saving the posts: 
Promise.all(pendingPromises)
.then(imagePaths => post.save()) /*<-- all the promises resolved without errors, now you can save*/
.catch(() => console.log('well that didnt work...'))

---

您需要学习JavaScript Promise语言的特性。你在文章中用async和Wait提到了这一点。将循环的每次迭代看作是向数组添加新的承诺。当在循环中启动的异步工作完成时，您将解析该迭代添加的承诺。在循环结束时，您将阻塞一个Promise.all，它等待数组中的所有承诺完成。我建议你坚持承诺，如果你在这方面有问题。。。经过研究。。。就这个话题发表一个问题。