Firebase Javascript check if storage exist before running function

Question

is there a way to check if the storage first exists before firing the getDownloadURL option?

Here is my code.

var storagedpurl = firebase.storage().ref(firebaseUser.uid + '/profilePicture/' + "displaypicture"); //URL to get current user dp
storagedpurl.getDownloadURL().then(function(url) { //Download dp from storage and display in circle img tag
  var firebaseimageurl = url;
  document.querySelector('img').src = firebaseimageurl;
}).catch(function(error) {
  console.log(error.code);
});

In the case where I do not have the storage folder for profilepicture, my console log will keep showing the error that says I do not have the storage object. Therefore I'd like it to only run the function if the storage object exists, is it possible?

Answer 1

No.

You have to download to check , if it exists or not. Firebase API responds with proper error telling you why it failed.

Use the catch block to handle errors:

.catch(function(error) {
  switch (error.code) {
    case 'storage/object_not_found': // <<< here you decide what to do when the file doesn't exist
      // File doesn't exist
      break;

    case 'storage/unauthorized':
      // User doesn't have permission to access the object
      break;

    case 'storage/canceled':
      // User canceled the upload
      break;

    ...

    case 'storage/unknown':
      // Unknown error occurred, inspect the server response
      break;
  }
});

A full list of error codes is available here .

Answer 2

To my best knowledge, the firebase storage designed in a way that the users request a file that only exists. Therefore non-existing file have to handled as error

See this documentation for how to handle this errors in storage

Otherwise, I would suggest you can use getDownloadUrl . which in turn returns a promise like below,

storageRef.child("file.png").getDownloadURL().then(onResolve, onReject);
function onResolve(foundURL) {
   //stuff
}
function onReject(error) {
   console.log(error.code);
}