in firestore/main/index.js [530:543]
async function getMultiple(db) {
// [START firestore_data_query]
const citiesRef = db.collection('cities');
const snapshot = await citiesRef.where('capital', '==', true).get();
if (snapshot.empty) {
console.log('No matching documents.');
return;
}
snapshot.forEach(doc => {
console.log(doc.id, '=>', doc.data());
});
// [END firestore_data_query]
}