Let's say, I need to send an email to all the members of the group when the group is complete:
export const sendEmailToNewMember = functions.firestore.document('group/{groupId}').onCreate(async (snapshot,context) => {
}
The collection group has subcollection members. I check if the member's count has incremented and matches the total number of members who can join a group. If the final member has joined, I need to send all the members an email saying the group is complete.
The data structure looks like the one shown below:
collection group {
membersCount: 9999,
totalMembers: 100000,
....
users subcollection
}
I tried accessing the collection through ref like so:
const usersRef = snap.ref.collection('users)
But, the result was undefined. For now, I access it using
await firestore().collection('group').doc(groupId).collection('users')
Is it possible to access the subcollection without awaiting it and from the snapshot itself?
The document() takes path to a document and not a field. So if you want to trigger this function when any of the fields in group document is updated then set the path to .document('group/{groupId}').
Also snapshot in onCreate() will then contain data of that group's document only (the document that triggered the function). You'll have to explicitly read the sub-collection.
It seems you want to send email to new member that joins a group. You can instead trigger the function when a new user is added in user's sub-collection as shown below:
// Here user's UID would be ID of sub-document
export const sendEmailToNewMember = functions.firestore.document('group/{groupId}/users/{userId}').onCreate(async (snapshot,context) => {
const { groupId, userId } = context.params;
}