how to perform OR query with transaction in cloud firestore?

Question

If any single doc exist in myCollection in which array contains any value of arr array then I do not wants to add new document in myCollection2 I want to run this query on cloud function.

firestore structure

    myCollection
              myDoc1
                  array:[1,2,3]
              myDoc2
              array:[5,8,7]*
   myCollection2 ....

---

How I am doing it

const arr=[2,5,8,9];

return db.runTransaction(async t=>{

  for(let i=0,i<arr.length<t++){
    await  t.get(db.collection('myCollection').where('array','array-contains'arr[i]).then(doc=>{
      if(doc.exists) throw new functions.http.httpError('internal','not available');
    })
  }

  return db.collection('mycollection2').add({
    //fields 
  });

});

is this right approach?

Answer 1

There is no way to do that. What you do is combine different queries which match your terms and combine them. Here is an example using rxjs and typescript

function getData(value1, value2)
{
    const scenario1 = this.afs.collection(`collection1`, ref => {
                let query: firebase.firestore.CollectionReference | f 
   firebase.firestore.Query = ref;
                query = query.where("field1", "==", value1);
                return query;

            }).snapshotChanges()
                .pipe(take(1))
                .pipe(
                    map(changes => {
                        return changes.map(a => {
                            const data = a.payload.doc.data() as CustomDataType;
                            data.docId = a.payload.doc.id;
                            return data;
                        })
                    })
                );


    const scenario2 = this.afs.collection(`collection1`, ref => {
                let query: firebase.firestore.CollectionReference | firebase.firestore.Query = ref;
                query = query.where("field1", "==", value2);
                return query;

            }).snapshotChanges()
                .pipe(take(1))
                .pipe(
                    map(changes => {
                        return changes.map(a => {
                            const data = a.payload.doc.data() as CustomDataType;
                            data.docId = a.payload.doc.id;
                            return data;
                        })
                    })
                );
            return forkJoin(scenario1,scenario2)
                .pipe(map((arr) => [...arr[0],...arr[1]] ));
}