如何在Firebase函数中执行firestore查询？

const admin = require('firebase-admin');
admin.initializeApp();
const db = admin.firestore();

const usersRef = db.collection('users');
const querySnapshot = await usersRef.get();
querySnapshot.forEach((doc) => {
  console.log(doc.id, '=>', doc.data());
});

const usersRef = db.collection('users');
const querySnapshot = await usersRef.where('age', '>=', 18).get();
querySnapshot.forEach((doc) => {
  console.log(doc.id, '=>', doc.data());
});

const usersRef = db.collection('users');
const querySnapshot = await usersRef.orderBy('age', 'desc').get();
querySnapshot.forEach((doc) => {
  console.log(doc.id, '=>', doc.data());
});