如何將返回 observable 的 function 轉換為箭頭 function？

Question

我有以下代碼可以正常工作。 我想要的是將 getSaveObs function 轉換為箭頭 function，這樣我就可以在存檔 function 中使用它。

private save(property: IProperty): void {
  // I want the getSaveObs logic to be moved here instead of a separate function
  this.getSaveObs(property)
   .subscribe(savedProperty => {
    this.property = savedProperty;
    this.propertyStorageService.storeProperty(this.property);
    this.propertyDetailsForm.get('id').setValue(this.property.id);
    // if new property, move to step 2
    if (!savedProperty.id) {
      console.log('New property, moving to step 2');
      if (this.clientId) {
        this.router.navigateByUrl('/clients/' + this.clientId + '/properties/' + this.property.id + '/' + '2');
      } else {
        this.router.navigate(['/properties', this.property.id, '2']);
      }
    }
  }, error => (console.error('Error adding/updating a property: ', error)));
}


private getSaveObs(property: IProperty): Observable<IProperty> {
  if (property.id) {
    if (this.clientId) {
        return this.clientPropertiesService.updateProperty(this.accountService.userIdentity.userId,                
           this.clientId, property);
    } else {
        return this.profileService.updateProperty(this.accountService.userIdentity.userId, property);
    }
  } else {
    // New property observable
    if (this.clientId) {
        return this.clientPropertiesService.createProperty(this.accountService.userIdentity.userId, 
           this.clientId, property);
    } else {
      return this.profileService.createProperty(this.accountService.userIdentity.userId, property);
    }
  }
}

這是返回 Observable 的調用方法之一

createUserProperty(property: IProperty, userDocument: 
    AngularFirestoreCollection): EntityResponseType {
    delete property.id;
    property.modifiedTs = firebase.firestore.Timestamp.now();
    property.createdTs = firebase.firestore.Timestamp.now();

    return from(userDocument.add(property))
      .pipe(
         map(res => {
         return {...property, id: res.id};
      })
    );
 }

Answer 1

為什么您認為箭頭 function 可以用於save(property: IProperty): void而普通的 function 不能？ 你想做什么？

---

不管任何 function 都可以像這樣變成箭頭 function

function someName(arg: ArgType): ReturnType {
  /*...function body...*/
}

成為

const someName = (arg: ArgType): ReturnType => {
  /*...function body...*/
}

所以在你的情況下，那是：

const getSaveObs = (property: IProperty): Observable<IProperty> => {
  if (property.id) {
    if (this.clientId) {
        return this.clientPropertiesService.updateProperty(this.accountService.userIdentity.userId,                
           this.clientId, property);
    } else {
        return this.profileService.updateProperty(this.accountService.userIdentity.userId, property);
    }
  } else {
    // New property observable
    if (this.clientId) {
        return this.clientPropertiesService.createProperty(this.accountService.userIdentity.userId, 
           this.clientId, property);
    } else {
      return this.profileService.createProperty(this.accountService.userIdentity.userId, property);
    }
  }
}