Firebase authWithCustomToken throwing an error instead of calling callback? - firebase

Question

I am following the example in the docs:
ref.authWithCustomToken(authToken, function(error, authData) {
if (error) {
console.log("Authentication Failed!", error);
} else {
console.log("Authenticated successfully with payload:", authData);
}
});
If I pass an invalid token to authWithCustomToken (e.g. authToken is undefined) , it throws an Error, rather than passing an error code to the callback. In other words, neither console.log is executed, but this error is thrown:
First argument must be a valid credential (a string).
Wrapping it in try catch solves the problem easily enough, but I didn't see any mention in the docs. Is it the intended behaviour?
In my use-case the token is passed through a url, so an undefined parameter is a possible error condition.

Answer 1

From firebase-debug.js:
if (!goog.isString(cred)) {
throw new Error(fb.util.validation.errorPrefix(fnName, argumentNumber, optional) + "must be a valid credential (a string).");
}
What probably happened:
You passed a non-string value as authToken so the error not happened in the Firebase (server) side, it happened in the client side (your side) so it will be not reported on the callback function but as Javascript exception in your code.
Possible workaround (I don't know why, but if you want)
If you want to pass a variable as authToken and it could not be a string, and you still want to get the "Wrong credentials" error, instead of type validation, then you need to force string conversion using:
var ref = new Firebase("https://<YOUR-FIREBASE-APP>.firebaseio.com");
var numberAuthToken = 212312312312312; // number
var stringAuthToken = String(numberAuthToken);
ref.authWithCustomToken(stringAuthToken, function(error, authData) {
if (error) {
console.log("Authentication Failed!", error);
} else {
console.log("Authenticated successfully with payload:", authData);
}
});
But it not makes sense for me. :)