Tags: 1.0 2.0 2.5 Privileged


The DataStoreChangeEvent interface of the Data Store API represents the event related to a record changed in the data store, i.e. this is returned once a change is made and the change event is fired (see DataStore.onchange for the handler).



In the following snippet we retrieve all the data stores on the device with the name "contacts", then we use DataStore.sync to create a cursor to use for syncing the app with the current "content" data store (displaying new items, etc.) This cursor is passed to the runNextTask() function that will deal with running through the updates in some way. Next, we include some code inside an onchange function so that when a change is made we return the DataStoreChangeEvent (e in this case), find out what type of operation the change is, and then take action based on this type (either adding or deleting a contact's information.)

navigator.getDataStores('contacts').then(function(stores) {
  var cursor = stores[0].sync();

  stores[0].onchange = function(e) {
    if (e.operation == 'removed') {
      // Delete the contact

    if (e.operation == 'added') {
      stores[0].get( {
        // Add the new contact

Operation types

The different operation types used in DataStoreChangeEvent are (see also the spec definitions):

Enumaration Description
added The record is added into the data store.
updated The record is updated in the data store.
removed The record is deleted from the data store.
cleared All records are deleted from the data store.