FireBase云功能:Promise.All的问题(Promise)

如果它对某人有用,我发现的解决方案是:

var promises = [];
var str="string containing data to replace with signed url";

storage.bucket().getFiles({ prefix: folderPath }).then(results => {
  const files = results[0];
  files.forEach(function(file) {

     promises.push( //the trick was here

       file.getSignedUrl(signedUrlConfig).then(signedUrls => {
         ...
         surl = signedUrls[0];
         str=str.replace("a",surl); //eg: replace with signed url.
         return str;
       });
     );
  });
  Promise.all(promises).then(() => {
    console.log(str); //str contains all signed url
  });
});

你好像在找

const promise = storage.bucket().file().download().then(str => {
//    ^^^^^^^^^                                   ^^^^^
    return storage.bucket().getFiles().then(results => {
//  ^^^^^^
        const files = results[0];
        for (const file of files) {
            …
            str = str.replace("t","a");
        }
        return str;
    //  ^^^^^^
    });
});

promise.then(str => { /*
^^^^^^^^^^^^ */
    console.log(str);
    return file.save(str); // should return a promise
});

你也不需要 new Promise 也不 Promise.all 在这里。但是,您可以使用后者删除嵌套,甚至可能运行 getFiles() 和 download() 同时,请参见 How do I access previous promise results in a .then() chain? .