Changes API: How to Subscribe to Document Changes

Single document changes can be observed using forDocument() method.

Syntax

store.changes().forDocument(docId);

Example

store.changes().forDocument("employees/1")
    .on("error", err => {
        //handle error 
    })
    .on("data", change => {
        switch (change.type) {
            case "Put":
                // do something
                break;
            case "Delete":
                // do something
                break;
        }
    });

To observe all document changes in particular collection use forDocumentInCollection() method. This method filters documents by @collection metadata property value.

Syntax

store.changes().forDocumentsInCollection(collectionName);
store.changes().forDocumentsInCollection(clazz);

Example

store.changes().forDocumentsInCollection(Employee)
    .on("data", change => {
        console.log(change.type + " on document " + change.id);
    });

or

const collectionName = store.conventions.getCollectionNameForType(Employee);
store.changes()
    .forDocumentsInCollection(collectionName)
    .on("data", change => {
        console.log(change.type + " on document " + change.id);
    });

To observe all document changes for documents with ID that contains given prefix use forDocumentsStartingWith() method.

Syntax

store.changes().forDocumentsStartingWith(docIdPrefix);

Example

store.changes()
    .forDocumentsStartingWith("employees/1") // employees/1, employees/10, employees/11, etc.
    .on("data", change => {
        console.log(change.type + " on document " + change.id);
    });

To observe all document changes use forAllDocuments() method.

Syntax

store.changes().forAllDocuments();

Example

store.changes().forAllDocuments()
    .on("data", change => {
        console.log(change.type + " on document " + change.id);
    });