Struggling to display data from Firebase Database in dropdown menu using Angular

Despite my extensive search efforts online, including watching YouTube videos and enrolling in Udemy courses, I have not been able to find the solution to my issue. My goal is to take an observable retrieved from Firebase and populate it into a dropdown menu.

Currently, I am successfully fetching data from Firebase and displaying it on the page as a list. However, I seem to be missing a key step in transforming this data into a dropdown selection.

Below is the code I am working with:

.ts

import { FormsModule } from '@angular/forms';
import { Component, OnInit, } from '@angular/core';
import { AngularFireDatabase, AngularFireList } from '@angular/fire/database';

@Component({
  selector: 'app-home-three',
  templateUrl: './home-three.component.html',
  styleUrls: ['./home-three.component.scss']
})

export class HomeThreeComponent  {
  jobCategory$;
  
  
  constructor(private db: AngularFireDatabase) { 
   
    }

    ngOnInit(){
      this.jobCategory$ = this.db.list('/jobCategory').valueChanges();
      }
  
  }

my .html

<div class="col-lg-4">
      <div class="form-group">
             <select>                 
                                        
                                               
               <option>All Categories</option>
               <option *ngFor="let jobCategories of jobCategory$" [ngValue]="jobCategories"> 
                                            {{ jobCategories }}  
                                       
                                    </select>
                                        <!--This needs to pull categories from database -->
                                        
                                                    
                                    </div>

I have attempted to convert the observable into an array using:

//this.jobCategory = Array.of(this.jobCategory$)

While this allowed me to display [object Object] in the dropdown, I have not been able to achieve the desired outcome. Any assistance would be greatly appreciated.

Answer №1

Initially, prioritize semantic clarity:

// Note the distinction between jobCategory (singular) and jobCategories$ (plural)
// Maintain the async pipe subscription
ngOnInit(){
      this.jobCategories$ = this.db.list('/jobCategory').valueChanges();
      // Double-check for categories presence
      this.jobCategories$.subscribe(categories => console.log(categories));
}
...
<option *ngFor="let jobCategory of jobCategories$ | async" [ngValue]="jobCategory"> 
                                            {{ jobCategory }}  
                                       
                                    </select>

Ensure to review the subscribe method. Verify that console.log displays the categories and not an empty array. It's possible that the query is returning an empty array, causing the absence of option tags.

Answer №2

Uncertain if removing the function call from valueChanges() will solve the issue, but it's worth a try.

*Additionally, follow the async suggestion mentioned earlier.

Therefore, this particular line should be modified as follows:

this.jobCategory$ = this.db.list('/jobCategory').valueChanges;

Answer №3

Opting for objects instead of lists is a wise choice. It simplifies accessing both values and keys, a technique that has proven effective for me.

db.object('/jobCategory')
  .valueChanges()
  .subscribe((input) => {
    this.jobCategories = input;
    console.log(this.jobCategories);
  });

The result will be presented in a key-value structure.

{1:"jobcategory1", 2:"jobcategory2", ...}

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