Is there a better way to catch javascript errors in clojurescript? - error-handling

Question

I've been working with firebase in clojurescript and I've attempted the advice here:
How to catch any Javascript exception in Clojurescript?
The code I have so far is:
(defn register [email password]
(try
(let [reg (.createUserWithEmailAndPassword (.auth firebase) email password)
_ (.log js/console reg)]
reg)
(catch :default e
(.log js/console "Register Error:" e))))
As I suspected the reason it's not been caught is that the evaluation could have been occurring later and this was to test the idea.
I have also tried:
(defn register [email password]
(try
(.createUserWithEmailAndPassword (.auth firebase) email password)
(catch :default e
(.log js/console "Register Error:" e))))
I call this using:
(apply register ((juxt :email :password) #app-state))
If I pass it an email I've already registered with I get as expected an auth/email-already-in-use error, but I can't catch it.
www.googleapis.com/identitytoolkit/v3/relyingparty/signupNewUser?key=AIzaSyDzsfz98Y6Pjl1n-uAzfI6GHWKqShFdRI4:1
POST https://www.googleapis.com/identitytoolkit/v3/relyingparty/signupNewUser?key=AIzaSyDzsfz98Y6Pjl1n-uAzfI6GHWKqShFdRI4 400 ()
firebase.inc.js:81
Uncaught
Qcode: "auth/email-already-in-use"
message: "The email address is already in use by another account."
__proto__: Error
(anonymous) # firebase.inc.js:81
How do I catch it? Or is the only way of handling this by using the raw javascript?
firebase.auth().createUserWithEmailAndPassword(email, password).catch(function(error) {
// Handle Errors here.
var errorCode = error.code;
var errorMessage = error.message;
// ...
});

Answer 1

Firebase auth is asynchronous. Javascript's (and, generally, Clojurescript's) try...catch does not work in callbacks. Call the catch function provided by the Firebase handler with your callback on error, like this - this is the literal translation of the JS code in your post above:
(defn register [email password]
(.. firebase auth (createUserWithEmailAndPassword email password)
(catch (fn [e] (.log js/console "Register Error:" e))))