How to workaround firestore batch limit in cloud functions [duplicate] - node.js

Question

This question already has answers here:
How can I update more than 500 docs in Firestore using Batch?
(8 answers)
Closed 3 years ago.
I am trying to delete entire user records from firestore using cloud functions but encounters the next error
INVALID_ARGUMENT: maximum 500 writes allowed per request
How to workaround this?
const functions = require('firebase-functions');
const admin = require('firebase-admin');
admin.initializeApp();
exports.deleteUserContacts = functions
.runWith({
timeoutSeconds: 540,
memory: '2GB'
})
.https.onCall((data,context) => {
// ...
return admin.firestore().collection('contacts').where('uid','==',context.auth.uid).get()
.then(snap => {
if (snap.size === 0) {
console.log(`User ${context.auth.uid} has no contacts to delete`);
return 'user has no contacts to delete';
}
let batch = admin.firestore().batch();
snap.forEach(doc => {
batch.delete(doc.ref)
});
return batch.commit(); //INVALID_ARGUMENT: maximum 500 writes allowed per request
})
.then(() => {
console.log(`Transaction success on user ${context.auth.uid}`);
return 'Transaction success';
})
.catch(error => {
console.log(`Transaction failure on user ${context.auth.uid}`,error);
throw new functions.https.HttpsError(
'unknown',
'Transaction failure'
);
});
});

Answer 1

To summarize final solution according to Stefan as worked for me.
If any error, please comment
const functions = require('firebase-functions');
const admin = require('firebase-admin');
admin.initializeApp();
exports.deleteUserContacts = functions
.runWith({
timeoutSeconds: 540,
memory: '2GB'
})
.https.onCall((data,context) => {
//...
return admin.firestore().collection('contacts').where('uid','==',context.auth.uid).get()
.then(snap => {
if (snap.size === 0) {
console.log(`User ${context.auth.uid} has no contacts to delete`);
return 'user has no contacts to delete';
}
const batchArray = [admin.firestore().batch()];
let operationCounter = 0;
let batchIndex = 0;
snap.forEach(doc => {
batchArray[batchIndex].delete(doc.ref);
operationCounter++;
if (operationCounter === 499) {
batchArray.push(admin.firestore().batch());
batchIndex++;
operationCounter = 0;
}
});
batchArray.forEach(
async batch => await batch.commit()
);
return 'function ended';
})
.then(() => {
console.log(`Transaction success on user ${context.auth.uid}`);
return 'Transaction success';
})
.catch(error => {
console.log(`Transaction failure on user ${context.auth.uid}`,error);
throw new functions.https.HttpsError(
'unknown',
'Transaction failure'
);
});
});

Answer 2

As you might know this is due to the limit to transactions and batched writes, in order to circumvent that limitation I found this SO post of another person that had a similar issue to you.
Most of the recommendations are batching it under 500 and then commiting.
Here, have a look at the solution here.
Hope this helps.