1const userRef = db.collection('documents').doc('document_id');
2const increment = firebase.firestore.FieldValue.increment(1);
3
4userRef.update({ FieldToIncrease: increment });
1const userRef = db.collection('documents').doc('document_id');
2const decrement = firebase.firestore.FieldValue.increment(-1);
3
4userRef.update({ fieldToDecrease: decrement });