Firebase Version 9 using multiple conditional where clauses-CodePudding

I'm updating a project from Firebase Version 8 to Version 9. I have conditional filtered queries that used to be structured as follows:

let query = db.collection("collectionName").orderBy("timestamp")

if (filters.selectedStaff) {
    query = query.where("id", "==", filters.selectedStaff.id);
    }
if (filters.selectedStudent) {
    query = query.where("studentIDs", "array-contains", filters.selectedStudent.id);
    }

Then the query gets executed in a hook that rerenders everytime the filters change. Using Version 8, this works perfectly.

In version 9, queries are now build to follow a format where each query is passed as a parameter to the query function. A normal query would look like:

query(collection(db, "collectionName"), where("id", "==", filters.selectedStaff.id), where("studentIDs", "array-contains", filters.selectedStudent.id), orderBy("timestamp"))

You can still store the where function as a variable, and pass that variable as a parameter to the query function:

let w1 = where("id", "==", filters.selectedStaff.id)
let w2 = where("studentIDs", "array-contains", filters.selectedStudent.id)
query(collection(db, "collectionName"), w1, w2, orderBy(timestamp))

But, the problem I haven't figured out how to solve, is how to make where clauses conditional. It doesn't seem like firebase allows a where clause value to be any. For example, making w1 default to:

let w1 = where("id", "==", "*")

If you try to make the operator also a variable and default to anything other than ==, like != :

let w1 = where("id", "!=", "")

Firebase forces you to set the primary sort by the field in the where clause which won't working if you're trying to sort by another field like I am (timestamp).

Ultimately, the workaround that works is to create a field in each document that has the same value, like a boolean true value and then set all your where clauses to be equal to that initially, and then dynamically change:

let w1 = where("randomField", "==", true)
let w2 = where("randomField", "==", true)
if(filters.selectedStaff){
    w1 = where("id", "==", filters.selectedStaff.id)
}
if(filters.selectedStudent){
    w2 = where("studentIDs", "array-contains", filters.selectedStudent.id)
}
query(collection(db, "collectionName"), w1, w2, orderBy(timestamp))

While this works, it feels like a really unnecessary workaround and I wanted to see if anyone know of a better way to accomplish the same outcome.

CodePudding user response：

You can keep using the existing logic, it's only the syntax that has changed. Try refactoring the code as shown below:

let q = query(collection("db", "collectionName"), orderBy("timestamp")); 

if (filters.selectedStaff) {
  q = query(q, where("id", "==", filters.selectedStaff.id));
}

if (filters.selectedStudent) {
  q = query(q, where("studentIDs", "array-contains", filters.selectedStudent.id));
}

const snapshot = await getDocs(q);

Another approach would be to conditionally push those conditions in an array:

const conditions = [orderBy("timestamp")]


if (filters.selectedStaff) {
  conditions.push(where("id", "==", filters.selectedStaff.id));
}

if (filters.selectedStudent) {
  conditions.push(where("studentIDs", "array-contains", filters.selectedStudent.id));
}

const q = query(collection(db, "collectionName"), ...conditions);
// Do note the spread operator                     ^

const snapshot = await getDocs(q);