Cloud function for firestore onWrite

Question

When I update or delete my document via firebase console my function triggered but when I log the field context.eventType I'm getting google.firestore.document.write instead of google.firestore.document.delete or google.firestore.document.update

Any clue please?

Code:

exports.useTest = functions.firestore
    .document("users/{userId}")
    .onWrite(async (handle, context) => {
    console.log("before", handle.before.data());
    console.log("after", handle.after.data());
    console.log("eventType", context.eventType);
});

Answer 1

According to this documentation , your Firestore functions will trigger the onWrite since it is triggered whether onCreate , onUpdate or onDelete is triggered. Regardless of the trigger, the onWrite will be shown.

There's also a guide to trigger a function for all changes to a document that you can follow:

exports.modifyUser = functions.firestore
    .document('users/{userID}')
    .onWrite((change, context) => {
      // Get an object with the current document value.
      // If the document does not exist, it has been deleted.
      const document = change.after.data();

      // Get an object with the previous document value (for update or delete)
      const oldDocument = change.before.data();

      // perform desired operations ...
    });

For further reference, you can refer to these documentations:

1. Trigger a function when a new document is created
2. Trigger a function when a document is updated
3. Trigger a function when a document is deleted

Answer 2

You can inspect handle :

if (!handle.before.exists && handle.after.exists) {
    // created
} else if (handle.before.exists && !handle.after.exists) {
    // deleted
} else {
    // updated
}