Question

你能告诉我如何将Angularfire2 / Firestore observable转换为promise吗？我试过如下所示。但它不起作用也没有错误。

.TS

  this.categories$ = this.categoryProvider.getAllContactCategories().valueChanges();
   const defaultCategories = await this.categories$.map((response) => response).toPromise();//after this line it won't execute
   await Promise.all(defaultCategories.map(async (c: Category) => {
   await this.categoryProvider.createCategory(c.name, project.id);
      }));

provider.ts

  getAllContactCategories(): AngularFirestoreCollection<Category> {
    return this.fireStore.collection(`contactCategories`);
  }

Answer 1

我这样做了：干杯：）

注意： 这仅用于更新master table的少数默认记录。不过是：）

import { first } from 'rxjs/operators';

this.categories$ = this.categoryProvider.getAllContactCategories().valueChanges();
const defaultCategories = await this.categories$.map(categories => {
     categories.forEach(async (c) => {
         await this.categoryProvider.createCategory(c.name, project.id);
      });
   }).pipe(first()).toPromise();

将Angularfire2 / Firestore observable转换为promise

1 个答案: