I'm wondering if it's possible to build firebase queries dynamically, at the moment I'm using a variable to determine if startAfter should be included or not.
As you can see this is causing duplicate code, for just one variable
export async function fetchUserPhotosPaginated(userId: string, lastUserPhoto?: QueryDocumentSnapshot): Promise<QuerySnapshot> {
if (lastUserPhoto) {
return await getDocs(query(
collection(db, 'photos'),
orderBy('createdAt', 'desc'),
startAfter(lastUserPhoto),
where('user.id', '==', userId),
limit(5)
))
}
return await getDocs(query(
collection(db, 'photos'),
orderBy('createdAt', 'desc'),
where('user.id', '==', userId),
limit(5)
))
}
startAfter(null), this did not give the intended effectlet q = query(...) to then update that query using q = q.startAfter(...) this also did not workThe second method of adding startAfter conditionally is correct but your syntax to update query is not. Try refactoring the function as shown below:
export async function fetchUserPhotosPaginated(userId: string, lastUserPhoto?: QueryDocumentSnapshot): Promise<QuerySnapshot> {
// Initial query
let q = query(collection(db, 'posts'), orderBy('createdAt', 'desc'))
// Add startAfter is lastUserPhoto is present
if (lastUserPhoto) q = query(q, startAfter(lastUserPhoto));
// Add remaining conditions
q = query(q, where('user.id', '==', userId), limit(5));
return await getDocs(q)
}
You can also add all conditions in an array as explained in following answer: