When it comes to updating multiple fields in a user document in Firebase, I am facing a dilemma. There are various fields that can be updated and have interactions with one another. Should I use a bunch of if statements, each triggering a write action if a condition is met, or should I opt for a single write at the end of the function for all potential changes? The latter option seems a bit cumbersome as it would require writing back the original value for unchanged fields. Is there perhaps a better approach that I am missing out on? What would be considered best practice in this scenario?
Let me illustrate what I currently have in place for updating fields individually:
export const userUpdate = functions.firestore
.document("users/{userID}")
.onUpdate(async (change) => {
const beforeData = change.before.data();
const afterData = change.after.data();
// Example: User levels up and gains more HP.
if(beforeData.userLevel != afterData.userLevel){
const newMaxHP = 15 + 5 * afterData.userLevel;
change.after.ref.update({
maxHp: newMaxHP
})
}
// Update user rating
if (beforeData.numberOfRatings != afterData.numberOfRatings) {
const newRating = calculateRating(beforeData.userRating, beforeData.numberOfRatings, afterData.latestRating);
change.after.ref.update({
userRating: newRating
})
}
// Replenish user funds if they drop to zero
if (afterData.money == 0){
change.after.ref.update({
money: 20
})
}
If I were to consolidate everything into a single write operation, each if statement would assign a value to a variable without directly updating the Firestore document. Additionally, each if statement would contain an else clause assigning the original value back to the field. Ultimately, there would be a single write at the end similar to this:
change.after.ref.update({
maxHp: newMaxHP,
userRating: newRating,
money: 20
})
I hope that clarifies things.
[Additional question regarding updating map values]
@Dharmaraj's solution works well, but I'm encountering difficulties when applying it to update a map value. Just to clarify, I'm working with Typescript.
Prior to using @Dharmaraj's approach, my code looked like this:
admin.firestore().collection("users").doc(lastPlayerAttacker).update({
"equipped.weapon.usesLeft": admin.firestore.FieldValue.increment(-1)
});
When implementing the update object, I tried the following method, but received the error "Object is of type 'unknown'":
const lastPlayerUpdates:{[key:string]:unknown} = {};
lastPlayerUpdates.equipped.weapon.usesLeft = admin.firestore.FieldValue.increment(-1);
admin.firestore().collection("users").doc(lastPlayerAttacker).update(lastPlayerUpdates);
Any insights on how I can resolve this issue?