Properly managing exceptions in your Ionic 2 application

Question

Properly managing exceptions in your Ionic 2 application

I have developed an ionic2 app that utilizes firebase authentication. I am currently facing an issue when handling the "auth/account-exists-with-different-credential" error, specifically when a user tries to log in with the same email using multiple providers (such as Google and Facebook).

constructor(public af: AngularFire,public navCtrl: NavController) {
    firebase.auth().getRedirectResult()
      .then(res=>{
        console.log('success',res)
      })
  .catch((err:any)=>{
    console.log(error.message)
    if (err.code=='auth/account-exists-with-different-credential'){
       doaccountlink();
    }
  })
  }



    fblogin(){
        firebase.auth().signInWithRedirect(new firebase.auth.FacebookAuthProvider())
      }

      gglogin(){
        firebase.auth().signInWithRedirect(new firebase.auth.GoogleAuthProvider())
      }

Although I am able to catch the error code in the catch block as expected, the problem arises when the exception continues to display in the console and on my page (as shown in the attached image). I am relatively new to JavaScript/TypeScript. In Java, if an error is already caught in the catch block, it should not continue to be displayed. Is there something wrong with my code? How can I prevent this exception from showing on my page?

https://i.sstatic.net/r79o8.png

angular typescript firebase ionic2 firebase-authentication

Answer 1

Answer №1

To gain a better understanding of the issue, it would be necessary to thoroughly debug your code as there may be another exception occurring elsewhere that is causing the displayed page. However, here are some useful tips:

The page shown with the exception is due to the presence of the IonicErrorHandler. You can locate this in your app.module.ts file within the providers array, where you will find the following line:
```
providers: [
    // services...
    { provide: ErrorHandler, useClass: IonicErrorHandler }
]
```
This essentially means that Ionic is extending Angular 2's default ErrorHandler with its own class. It's worth noting that this extension only occurs during development and not in production (more information can be found in the source code here).
If it suits the context of your app, you have the option to create your own error handler and manage exceptions using custom code. As demonstrated here, you can achieve this by implementing a new class that conforms to the ErrorHandler interface:
```
class MyErrorHandler implements ErrorHandler {
    handleError(err: any): void {
        // handle the error appropriately
    }
}
```
You can then replace the
```
{ provide: ErrorHandler, useClass: IonicErrorHandler }
```
with
```
{ provide: ErrorHandler, useClass: MyErrorHandler }
```

Answer 2

To gain a better understanding of the issue, it would be necessary to thoroughly debug your code as there may be another exception occurring elsewhere that is causing the displayed page. However, here are some useful tips:

The page shown with the exception is due to the presence of the IonicErrorHandler. You can locate this in your app.module.ts file within the providers array, where you will find the following line:
```
providers: [
    // services...
    { provide: ErrorHandler, useClass: IonicErrorHandler }
]
```
This essentially means that Ionic is extending Angular 2's default ErrorHandler with its own class. It's worth noting that this extension only occurs during development and not in production (more information can be found in the source code here).
If it suits the context of your app, you have the option to create your own error handler and manage exceptions using custom code. As demonstrated here, you can achieve this by implementing a new class that conforms to the ErrorHandler interface:
```
class MyErrorHandler implements ErrorHandler {
    handleError(err: any): void {
        // handle the error appropriately
    }
}
```
You can then replace the
```
{ provide: ErrorHandler, useClass: IonicErrorHandler }
```
with
```
{ provide: ErrorHandler, useClass: MyErrorHandler }
```

Properly managing exceptions in your Ionic 2 application

Answer №1

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