完成后上传任务getDownloadUrl()

Question

I need this general purpose utility method that accepts the file object and return me the url of the file after uploading, but some how I am getting a promise instead of the download URL.

I have tried all approached, i need ES6 async/await solution.

export const uploadFile = (file) => {
  let uploadTask = storage.ref(`products/${Date.now()}.${file.name.split('.').pop()}`).put(file);
  uploadTask.on(firebase.storage.TaskEvent.STATE_CHANGED, {
    'complete': () => {
      uploadTask.snapshot.ref.getDownloadURL().then((d) => {
        return d
      })
    }
  });
}

Answer 1

As explained in the doc, if you call then() on a UploadTask , you will get an object which "behaves like a Promise, and resolves with its snapshot data when the upload completes".

Therefore the following should do the trick.

export const uploadFile = (file) => {
  let uploadTask = storage.ref(`products/${Date.now()}.${file.name.split('.').pop()}`).put(file);
  return uploadTask.
    then(snapshot => {
      return snapshot.ref.getDownloadURL();
    })
    .then((url) => {
      return url
    });
}

---

Update following your comment:

You mention in the comments that you call the function as follows:

let files = state.images; 
for (let i = 0; i < e.target.files.length; i++) { 
   files = files.concat(e.target.files[i]); 
   let url = uploadFile(files[i])
   console.log(url)
}

However, the uploadFile() function is asynchronous and indeed, as a consequence, it returns a Promise. You should take that into account when calling it. For example, with a loop, you could call it as follows:

const promises = [];
let files = state.images; 
for (let i = 0; i < e.target.files.length; i++) { 
   files = files.concat(e.target.files[i]); 
   promises.push(uploadFile(files[i]));
}
Promise.all(promises)
 .then(urlsArray => {
    urlsArray.forEach(url => {
        console.log(url);
    })
  })

Answer 2

ES6 async await solution for others having similar problem:

export const uploadFile = async (file) => {
  let uploadTask = storage.ref(`products/${Date.now()}.${file.name.split('.').pop()}`).put(file);
  const snapshot = await uploadTask;
  const url = await snapshot.ref.getDownloadURL();
  return url;
}