Angular displays the error message TS2339, stating that the property 'handleError' is not found on the 'HeroService' type

Question

Angular displays the error message TS2339, stating that the property 'handleError' is not found on the 'HeroService' type

Hey everyone, I know there are already a few questions out there about Typescript compilation errors, but I'm facing a unique challenge that I can't quite figure out.

I'm currently working on the Angular Tour of Heroes app and trying to complete the section on Http. However, when I look at my hero.service.ts file, it's throwing this error:

error TS2339: Property 'handleError' does not exist on type 'HeroService'

While I understand that similar issues have been discussed before related to TypeScript configuration, the root cause behind this particular problem seems elusive.

As someone who is still getting a hang of TypeScript (and Angular), troubleshooting this on my own has proven to be a bit challenging.

This is how my code currently looks:

CODE:

// Code snippet here...

...

If you believe that there might be another version of this question elsewhere, please point me in that direction. Thanks for your help!

Appreciate it.

angular typescript

Answer 1

Answer №1

During my journey through the ToH tutorial, I stumbled upon a helpful tidbit in the "Error Handling" section of the HTTP chapter. Although it was briefly mentioned, it wasn't explicitly emphasized that adding the following code snippet to your "hero.service.ts" file is crucial (especially if you're prone to skimming information):

private handleError(error: any): Promise<any> {
    console.error('An error occurred', error); // for demo purposes only
    return Promise.reject(error.message || error);
 }

I simply inserted this code at the bottom within the HeroService class and everything fell into place. Hopefully, this solution proves effective for you too :).

Answer 2

During my journey through the ToH tutorial, I stumbled upon a helpful tidbit in the "Error Handling" section of the HTTP chapter. Although it was briefly mentioned, it wasn't explicitly emphasized that adding the following code snippet to your "hero.service.ts" file is crucial (especially if you're prone to skimming information):

private handleError(error: any): Promise<any> {
    console.error('An error occurred', error); // for demo purposes only
    return Promise.reject(error.message || error);
 }

I simply inserted this code at the bottom within the HeroService class and everything fell into place. Hopefully, this solution proves effective for you too :).

Answer 3

Answer №2

An issue has been encountered: Property 'handleError' is not found in the 'HeroService'

Remember, functions are also considered as properties.

getHeroes(): Promise<Hero[]> {
    return this.http.get(this.heroesUrl)
        .toPromise()
        .then(response => response.json().data as Hero[])
        .catch(this.handleError);  <=== Why isn't this method defined in HeroService?
}

To resolve this, you must add a handleError method within the HeroService class

handleError(error) {
  // handle the error appropriately
}

Seems like you might have overlooked this section of the tutorial :-)

Answer 4

An issue has been encountered: Property 'handleError' is not found in the 'HeroService'

Remember, functions are also considered as properties.

getHeroes(): Promise<Hero[]> {
    return this.http.get(this.heroesUrl)
        .toPromise()
        .then(response => response.json().data as Hero[])
        .catch(this.handleError);  <=== Why isn't this method defined in HeroService?
}

To resolve this, you must add a handleError method within the HeroService class

handleError(error) {
  // handle the error appropriately
}

Seems like you might have overlooked this section of the tutorial :-)

Answer 5

Answer №3

Incorporating the instructions provided in the tutorial, it is essential to include the subsequent method within hero.service.ts file:

private handleErrors<T>(operation = 'action', result?: T) {
    return (error: any): Observable<T> => {
      console.error(error);
      this.log(`${operation} was unsuccessful: ${error.message}`);
      return of(result as T);
    }
}

Answer 6

Incorporating the instructions provided in the tutorial, it is essential to include the subsequent method within hero.service.ts file:

private handleErrors<T>(operation = 'action', result?: T) {
    return (error: any): Observable<T> => {
      console.error(error);
      this.log(`${operation} was unsuccessful: ${error.message}`);
      return of(result as T);
    }
}

Angular displays the error message TS2339, stating that the property 'handleError' is not found on the 'HeroService' type

Answer №1

Answer №2

Answer №3

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