Angular 6: Transform object and add to array

Question

Angular 6: Transform object and add to array

My service includes a method called getCategory() that retrieves categories from the server. The method looks like this:

getCategory(): Observable<CategoryModel[]> {
    return this.http.get<CategoryModel[]> (this.productUrl)
        .pipe(
            catchError(this.handleError('getHeroes', []))
        );
}

Within my component, I aim to store the retrieved data in an array named categoryList: CategoryModel[]; using the following method:

getCategory(): void {
        this.dataStorageServiceService.getCategory()
            .subscribe(
                (categories: CategoryModel[]) => {
                    this.categoryList = categories;
                    console.log(this.categoryList)
                }
            }

The output of categoryList is displayed as an Object, and unfortunately, I am unable to render it on the template.

angular typescript

Answer 1

Answer №1

If you find yourself receiving an object instead of an array, there are two solutions available. You can either convert your object to an array or utilize the KeyValuePipe in your HTML template -

 <div *ngFor="let category of categoryList | keyvalue">
      {{category.key}}:{{category.value}}
  </div>

To learn more, please visit - https://github.com/angular/angular/blob/master/CHANGELOG.md#610-beta1-2018-06-13

Answer 2

If you find yourself receiving an object instead of an array, there are two solutions available. You can either convert your object to an array or utilize the KeyValuePipe in your HTML template -

 <div *ngFor="let category of categoryList | keyvalue">
      {{category.key}}:{{category.value}}
  </div>

To learn more, please visit - https://github.com/angular/angular/blob/master/CHANGELOG.md#610-beta1-2018-06-13

Answer 3

Answer №2

If you're working with Firebase, keep in mind that objects are preferred over arrays. For more information on this best practice, check out this article.

To work around this, one approach is to transform the object into an array when retrieving it from your service:

return this.http.get<CategoryModel[]> (this.productUrl)
  .pipe(
    map(products => {
      return Object.values(products);

      // Alternatively

      return Object.keys(products).map((keyName) => {
        return {id: keyName, product: products[keyName]};
      });
    }),
    catchError(this.handleError('getHeroes', []))
  );

Answer 4

If you're working with Firebase, keep in mind that objects are preferred over arrays. For more information on this best practice, check out this article.

To work around this, one approach is to transform the object into an array when retrieving it from your service:

return this.http.get<CategoryModel[]> (this.productUrl)
  .pipe(
    map(products => {
      return Object.values(products);

      // Alternatively

      return Object.keys(products).map((keyName) => {
        return {id: keyName, product: products[keyName]};
      });
    }),
    catchError(this.handleError('getHeroes', []))
  );

Answer 5

Answer №3

Another option is to utilize the following code snippet:

categoryList : CategoryModel[] = [];

Subsequently, you can add the user object and convert it into an array like this:

this.categoryList.push(<<insert data to be pushed>>);

Answer 6

Another option is to utilize the following code snippet:

categoryList : CategoryModel[] = [];

Subsequently, you can add the user object and convert it into an array like this:

this.categoryList.push(<<insert data to be pushed>>);

Angular 6: Transform object and add to array

Answer №1

Answer №2

Answer №3

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