How to upload multiple files to Firebase?

Question

Is there a way to upload multiple files to Firebase storage. It can upload single file within single attempt as follows.

fileButton.addEventListener(\'chang         


        

Answer 1

We can Combine multiple Promises like this

Promise.all([promise1, promise2, promise3]).then(function(values) {
  console.log(values);
});

And we can Chain Promise like this

return myFirstPromise.then( (returnFromFirst) => {
    //Do something
    return secondPromise();
}).then( (returnFromSecond) => {
    //Do something
    return thirdPromise();
}).then( (returnFromThird) => {
    //All Done
}).catch( (e) =>{}
    console.error("SOMETHING WENT WRONG!!!");
);

Idea is to combine upload file promises with Promise.all & chain them together to get download URLS after each upload

      Promise.all(
            //Array.map creates a new array with the results 
          // of calling a function for every array element. 
          //In this case Array of "Promises"
            this.state.filesToUpload.map(item => 
             this.uploadFileAsPromise(item))
          )
            .then(url => {
              console.log(`All success`);

              //Handle Success all image upload

            })
            .catch(error => {
              console.log(`Some failed: `, error.message);

              //Handle Failure some/all image upload failed             
            });


  //return a promise which upload file & get download URL 
  uploadFileAsPromise(imageFile) {
        // the return value will be a Promise
        return storageRef
          .child("images/users/" + imageFile.name)
          .put(imageFile.file) 
          .then(snapshot => {
            console.log("Uploaded File:", imageFile.name);
            return snapshot.ref.getDownloadURL().then(downloadURL => {
              //promise inside promise to get donloadable URL
              console.log("File available at", downloadURL);
              );
            });
          })
          .catch(error => {
            console.log("Upload failed:", imageFile.name, error.message);
          });
      }