Array of operators for a Firestore Query

Question

I have this method in a Angular project:

  getData(collection: string, field: string, operator: WhereFilterOp, value: string) {
    return new Promise<any>((resolve, reject) => {
      this.afs.collection(collection, ref => ref.where(field, operator, value)).snapshotChanges().subscribe(snapshots => {
        resolve(snapshots);
      })
    })
  }

It works fine, but I have points in my system that I need more operators in my queries, how I really don't like to write code I want to pass a array of operators for a single method that resolve any query I wish to create a method like this:

  getData(collection: string, query: FirestoreQuery[], value: string) {
    return new Promise<any>((resolve, reject) => {
      this.afs.collection(collection, ref =>
      query.forEach(x => {
        ref.where(x.field, x.operator, x.value);
      })
      ).snapshotChanges().subscribe(snapshots => {
        resolve(snapshots);
      })
    })
  } 

I created a model to tipify the array of operators:

import { WhereFilterOp } from "@firebase/firestore-types";

export class FirestoreQuery {
    field: string;
    operator: WhereFilterOp;
    value: string;
}

Anybody can help to create this method or show me other way to pass a array of operators for a single getData method for my system. Write code is boring. I need get focused in my solution.

---

AskFirebase

Answer 1

You can use a reducer function to combine the queries.

import { WhereFilterOp } from '@firebase/firestore-types';

getData(collectionName: string, ...queries: any[]): Observable<any> {
  const collection = this.db.collection(collectionName, ref => {
    return queries.reduce((accumulator, query) => {
      const [fieldPath, opString, value] = query;

      return accumulator.where(fieldPath, opString as WhereFilterOp, value);
    }, ref);
  });

  return collection.snapshotChanges();
}

// Usage
getData('sampleCollection', ['foo', '>', 0], ['foo', '<', 10]);