how to check if file exists in Firebase Storage?

Question

When using the database you can do snapshot.exists() to check if certain data exists. According to the docs there isn't a similar method with storage.

https://firebase.google.com/docs/reference/js/firebase.storage.Reference

What is the proper way of checking if a certain file exists in Firebase Storage?

Answer 1

You can use getDownloadURL which returns a Promise, which can in turn be used to catch a "not found" error, or process the file if it exists. For example:

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

Answer 2

Firebase added an .exists() method. Another person responded and mentioned this, but the sample code they provided is incorrect. I found this thread while searching for a solution myself, and I was confused at first because I tried their code but it always was returning "File exists" even in cases when a file clearly did not exist.

exists() returns an array that contains a boolean. The correct way to use it is to check the value of the boolean, like this:

const storageFile = bucket.file('path/to/file.txt'); storageFile   .exists()   .then((exists) => {         if (exists[0]) {           console.log("File exists");         } else {           console.log("File does not exist");         }      }) 

I'm sharing this so the next person who finds this thread can see it and save themselves some time.