DataStoreChangeEvent.id

The id read-only property of the DataStoreChangeEvent interface returns the identifier of the changed record in the data store. This must return null if the operation is cleared.

Syntax

myId = e.id;

Value

A DataStoreKey.

Example

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 task the change was, and then take action based on this type (either adding or deleting a contact's information.)

The deleteContact() and loadContact() functions are passed e.id to use in their functionality.

navigator.getDataStores('contacts').then(function(stores) {
  var cursor = stores[0].sync();
  runNextTask(cursor);
  stores[0].onchange = function(e) {
    if (e.operation == 'removed') {
      // Delete the contact
      deleteContact(e.id);
    }
    if (e.operation == 'added') {
      stores[0].get(e.id).then(function(obj) {
        // Add the new contact
        loadData(obj,e.id);
      });
    }
  }
});

Specifications

The discussion concerning this API's creation happened in various Mozilla mailing lists and other places. A summary of the discussion and further pointers can be found on the Mozilla Wiki. For further feedback and questions, send mail to the dev-webapi mailing list.

Browser compatibility

See also

• Using the Data Store API
• Data Store Contacts Editor example
• Data Store Contacts Viewer example changeevent version
• Data Store Contacts Viewer example