Firestore - I want to dynamically add where statements to my collection

Question

Tech: I'm using Angular 7, Firestore, GeoFireX.

Outcome I want: I want to add .where queries if that query is required by the users. For example below I have four .wheres. I might only need two sometimes and therefore will only want to add two using maybe an if statement if user search by sector and brand (see method: basicQueryBuilder)

The code below works, but is not dynamic.

Additionally, can a this.geo.collection from GeoFireX have a .limit(20) just like a normal collection can?

Current Attempt:

  public getFirestoreJobs(queryType: string, limit: number, pageSize: number): Observable<any> {
    limit = limit + pageSize;

    if (queryType === 'geo') {
      const collection = this.geoQueryBuilder();
      const center = this.geo.point(51.5074, 0.1278);
      const radius = 20;

      return collection.within(center, radius, 'point');
    } else {
      const collection = this.basicQueryBuilder();

      return collection.valueChanges();
    }
  }

  public geoQueryBuilder(): any  {
    return this.geo.collection('jobs', ref => ref
      .where('sector', '==', 'teacher')
      .where('brand', '==', 'all')
      .where('payType', '==', 'salary')
      .where('tags', 'array-contains', 'salary'));
  }

  public basicQueryBuilder(): any {
    return this.angularFirestore.collection('jobs', ref => ref
      .where('sector', '==', 'teacher')
      .where('brand', '==', 'all')
      .where('payType', '==', 'salary')
      .where('tags', 'array-contains', 'salary').limit(20));
  }

Second attempt:

  let query = this.angularFirestore.collection('jobs');
  query = query.where('sector', '==', 'teacher');
  query = query.where('brand', '==', 'all');

  return query.valueChanges();

Error I get:

error TS2322: Type 'Query' is not assignable to type 'CollectionReference'.

Firestore queries use the builder pattern, so you can deal with each stage of the build conditionally by reassigning to some object that represents the current stage of the build. — Doug Stevenson, Feb 12 '19 at 22:22
@DougStevenson the question you labelled this as a duplicate with doesnt work using the query - query.where — AngularM, Feb 12 '19 at 22:33
It should. You'll need to be more specific about what exactly does not work. — Doug Stevenson, Feb 12 '19 at 22:35
@DougStevenson I've added a second attempt above. But I get an error. See above change please. Thanks — AngularM, Feb 12 '19 at 22:40
It looks like you need to conditionally apply the filters inside the callback function that accepts `ref`, not after it. I don't know enough about the angular wrapper for Firestore to try this myself, so I'll remove the dup. — Doug Stevenson, Feb 12 '19 at 22:45
Thank you. I've removed angularfire for this and I just do a normal firestore call. I get this error: error TS2322: Type 'Query' is not assignable to type 'CollectionReference'. — AngularM, Feb 12 '19 at 22:46
So slightly biased, but you could use `geofirestore` which behaves more like regular Firestore (so you can assign your query/collection and dynamically chain and reassign your query). It also supports the `limit` method, however there are some performance considerations. Also it doesn't return Observables, like the plain Firestore library, but you can use RxJS and create your own Observables. — MichaelSolati, Feb 13 '19 at 04:34
Thanks Michael, whats the database fields per document? The document says: g: string; l: GeoPoint; d: DocumentData; But those dont return anything — AngularM, Feb 13 '19 at 10:28
MichaelSolati, do you have pagination for your geofire? I need to use startAfter / StartAt e.g. so I can get 20 new results at a time. Is this possible? — AngularM, Feb 13 '19 at 14:57

score 7 · Answer 1 · answered Feb 16 '19 at 18:37

import {Query, QueryFn } from '@angular/fire/firestore';

    this.angularFirestore.collection('jobs', ref => {
    let query : Query = ref;
    if(condition1) {
     query = query.where('sector', '==', 'teacher');
    }
    if(condition2) {
     query = query.where('brand', '==', 'all');
    }
    return query;
    })

Firestore - I want to dynamically add where statements to my collection

1 Answers1