Removed unnecessary trycatch blocks where the error would propagate anyways ( ex. try{ } catch {throw err} )
Added error handling to the loadUser() function using a try-catch block to catch any errors that may occur while making API requests.
Modified the signIn() function to use a Promise to handle any errors that may occur while authenticating a user and added error handling to the Promise's reject() method.
Simplified the signIn() function by reducing code duplication.
try{ } catch {throw err})