I want to create a function that checks if a collection in Firestore exists and if it exist I want it to add the value given by the user to the value stored in the document inside the collection
My approach:
items.forEach(item=>
User && db.collection("users").doc(Uid).collection("basket").where( "id" , "==" , item.id)
.get().then(function(querySnapshot) {
if (querySnapshot.empty) {
// DO SOMETHING
}
else {
db.collection("users").doc(Uid).collection("basket").where("id" == item.id)
.get().then((docs) => {
docs.forEach((doc) =>{ doc.ref.set({
quantity : firebase.firestore.FieldValue.increment(item.quantity)
})}).then(setLocked(true))
})
}
})
)
however it shows the following error :
Unhandled Rejection (TypeError): Cannot read properties of undefined (reading 'ut')
I doubled check the code and it turns out that the error comes from the beginning of the query the else statement however there is nothing wrong with it
As Stf_F commented, you can either pass merge: true to the set call:
docs.forEach((doc) =>{
doc.ref.set({
quantity : firebase.firestore.FieldValue.increment(item.quantity)
}, { merge: true }) // 👈
})
or you can use update:
docs.forEach((doc) =>{
doc.ref.update({ // 👈
quantity : firebase.firestore.FieldValue.increment(item.quantity)
})
})
The .then(setLocked(true)) makes no sense, since forEach doesn't return a promise.